Many superheroes have a signature weapon that they rely on. These items are often associated specifically with them. Captain America has his shield, Wonder Woman has her golden lasso. Green Lantern has his power ring, and so on. These are weapons that aid them significantly in fighting evil, and fans look forward to seeing how they will be utilized.

Thor has a very distinct signature weapon. We're talking, of course, about Mjolnir. This powerful hammer has been by his side during many of his most memorable adventures. What non-hardcore fans may not know is that Mjolnir is only one tool in his arsenal. The Asgardian god has others at his disposal, including Stormbreaker. It's an alternate version of Mjolnir, serving several of the same functions. The thing that differentiates it is that one end of its head is a hammer, while the other is an ax.

Interest in Stormbreaker, which is alternately known as Ultimate Mjolnir, has spiked following its appearance in Avengers: Infinity War, where Thor introduces it to audiences during a crowd-pleasing moment. If Stormbreaker is new to you, or if you just want to learn a little more about it, we've got a thorough primer to provide all the information you need.

Here are 15 Crazy Facts About Thor's Stormbreaker.

It was originally made for someone else

Beta Ray Bill Thor Marvel

Perhaps the single most surprising thing about Stormbreaker is that it wasn't made for Thor. It was actually made for someone else, specifically the Korbinite named Beta Ray Bill.

To understand the history, you have to go back to 1984's The Mighty Thor #339. Thor and Bill battled after the former crashed into the latter's ship. Bill emerged victorious and was granted his opponent's hammer as a prize. Although the rightful victor, Bill began to have some second thoughts about taking it from the one who wielded it for so long.

To make up for this, Odin -- who oversaw the match -- decided to have a new weapon made specifically for Bill. It would essentially be the same as Mjolnir, it just wouldn't be Thor's Mjolnir. With that, Stormbreaker was born.

Avengers: Infinity War changes the hammer's backstory considerably. In the film's version, the Mjolnir-less Thor tells the Guardians of the Galaxy that he needs a new weapon in order to help defeat Thanos. He suggests they go to Nidavellir to have the dwarfs who live there cast him a new hammer of equal or greater strength.

The change was almost certainly necessitated by the fact that Beta Ray Bill has not been part of the MCU to this point.

It was made with magic, not star power

Stormbreaker being forged

Where does a mighty weapon like Stormbreaker come from? The answer may surprise you.

After deciding to gift Beta Ray Bill with a hammer of his own, Odin went to the dwarfs of Nidavellir, who live and work in caverns. Specifically, he sought out his old friend Eitri and requested that something similar to Mjolnir be made. Following a lengthy negotiation, Eitri agreed and ordered his colleagues to get to work. They forged a mold, which Odin infused with his magic. Bill then pulled out his new hammer from that mold, dubbing it Stormbreaker, and returned Mjolnir to Thor.

All of this leads to the second question: What, exactly, is something like this made of? The dwarfs cast Stormbreaker out of Uru, an extremely durable, virtually indestructible substance. One of the main properties of Uru is that it naturally absorbs various forms of energy, making it a versatile tool in the midst of battle. Even better, once charged up, it can expel that energy back out in a forceful manner.

Uru, which is mined by the dwarfs for use in making weapons for Asgardians, was also used in the making of Mjolnir and Thor's battle ax Jarnbjorn, among many others.

Sif had to fight a dwarf for it

Sif and Throgg battle

When Odin approached Eitri about casting the mold for a new hammer, he did not receive an automatic yes. The dwarf had one very specific condition.

There were some unresolved tensions between the two, which Eitri wanted resolved before agreeing to do any more work for Odin. He proposed that Asgard send a female warrior to battle his people's own champion. If the fighter from Asgard won, he would make the weapon. If not, she would become the dwarf champion's personal possession.

Odin's pick was Sif, the brother of Heimdall and a romantic interest of Thor. Her opponent was Throgg, a dwarf who used his slightly larger size to intimidate and coerce the others. This is the reason why Eitri was so eager to have him defeated. The two engaged in a fierce battle, which ended in victory for Sif and a bout of unconsciousness for Throgg.

Eitri was elated, especially given that being defeated by a woman would bring substantial embarrassment to Throgg, to the degree that he might not show his face in public again anytime soon. With the outcome he desired, Eitri ordered Stormbreaker to be forged.

Had Sif not won, the hammer would never have come into creation.

Striking power and force projection

Thor and Beta Ray Bill fighting each other

Hammers are made for one purpose - namely pounding something. It stands to reason, then, that Stormbreaker would be very good in that capacity. In fact, it's downright amazing. Force projection is one of its most significant powers.

Once charged up with energy, a single strike from its blunt end is enough to create a devastating impact, sending out tremors of energy to destroy whatever is in its path.

That proves useful in situations where multiple enemies must be dispatched of as quickly as possible. We see this ability in full effect during the Battle of Wakanda sequence in Avengers: Infinity War.

A veritable army of evil creatures penetrates the domed shield protecting Black Panther's homeland. Captain America, Black Widow, and the Dora Milaje attempt to fight them off, to no avail. Suddenly, down from the sky comes Thor, smashing Stormbreaker into the Wakandan ground as he lands and creating a wave of power that wipes out a wide swath of the invaders. That moment proves to be a real crowd-pleaser, as the Asgardian god has been largely powerless up to that point in the movie.

Stormbreaker has been used in similar ways throughout the comics. Enemies who find themselves on the receiving end of its smashing ability are toast.

Worthiness assessment

Stormbreaker worthiness inscription

Stormbreaker shares many qualities in common with Thor's other trusty weapon, Mjolnir. Perhaps the most significant of them is its ability to assess “worthiness.” In other words, it can only be lifted by those of impeccable moral character.

Thor, of course, has no trouble wielding either one, as he is the very definition of worthiness. Others are not so lucky. There are several notable tales of Stormbreaker being selective in who may use it, and when.

In Beta Ray Bill: Godhunter, the title character attempts to end Galactus by destroying any planet from which he attempts to feed, thereby causing him to starve. This aggressive quality eventually renders him unable to pick up Stormbreaker. Only after reversing course and saving Galactus following a vicious attack from an alien race does he regain his privileges.

For another example of its selective nature, look no further than the Thor Corp. It was comprised of three hammer-holding heroes – Beta Ray Bill, Dargo Ktor, and Eric Masterson, the latter of whom was known as “Thor 2.”

During a fight against Loki, Eric was able to grab Stormbreaker and use it in battle. Few would have been able to do this, but because he was another iteration of Thor, Eric was granted the honor of its many uses.

Thor once rejected it

Stormbreaker

You'd think that the chance to own a weapon like Stormbreaker would be something Thor would never up, right? It's powerful and comes equipped with all kinds of features that prove useful. And yet, the Asgardian hero rejected Stormbreaker in one of the comic book stories. Not because it wasn't worthy of him, but because he wasn't worthy of it.

In the Unworthy Thor storyline, Jane Foster achieves worthiness and is able to claim Mjolnir as her own. That sends Thor – referred to as Odinson – on a quest to find a new hammer. A long search ensues, culminating with him having the opportunity to claim Ultimate Mjolnir. Surprisingly, he doesn't take it, proclaiming, “This is not my hammer.

Why it up? Because he doesn't feel he is worthy of such a powerful object.

Gorr the Butcher, a villain who targeted gods, previously told him that gods were unworthy of worship and that their arrogance would ultimately destroy mankind. Thor ignored those words until Nick Fury later tells him that “Gorr was right,” sending him into an existential crisis. This makes him doubt his own worthiness, which, in turn, causes him to decide that Ultimate Mjolnir doesn't belong in his hands.

The power of recall

Thor vs beta ray bill

Imagine, for a moment, that you are a superhero. You have a powerful weapon with multiple uses. If you know that you will be going into battle, odds are good that you have it with you. What happens if you find yourself in unexpected trouble, though? Or, just as bad, what if you somehow become separated from it in the heat of an intense fight with a menacing enemy? Thor has that covered.

Stormbreaker will come to him. Like Mjolnir, it has the power of recall.

If Thor is battling bad guys, he can give it a throw, allowing it to forcefully glide through the air, striking one enemy or a string of them. Once that action is completed, it will immediately make its way back, so that he will be ready to hurl it again whenever needed.

The boomerang-like quality is indespensible because Thor doesn't need to go and retrieve it after every use.

If, for any reason, Thor doesn't have Stormbreaker on his person, there's no need for him to worry. He can summon his weapon, and it will seek him out, delivering itself right into the palm of his hand. No matter where he is or what's happening around him, if Thor needs Stormbreaker, it will find its way to his side.

The ability to open portals

Beta Ray Bill and Thor - Stormbreaker

As with many superheroes, Thor does a lot of traveling in his adventures. Because he hails from a far-away land where things commonly require his attention, he frequently needs to zip back and forth between Earth and Asgard. Other times, he has to move between various locations as part of his duties as a protector. Thor must get to where enemies are attacking, or where someone requires assistance. Using Stormbreaker provides a means for doing these things with expediency.

When Thor needs to race to a different location, he can use the weapon to open a portal that will rapidly get him where he needs to be.

This significantly increases his response time in an emergency, which is important when the stakes are high. When he has to go back home to Asgard, Stormbreaker provides a handy means of getting there. It has the capability to summon a beam somewhat similar to the bifrost, ensuring Thor a direct route.

As a member of the Star Masters, Beta Ray Bill successfully averted catastrophe using this same power. A meteor with a small black hole at its center was heading toward Earth. Silver Surfer destroyed the meteor, but the black hole kept on going. Bill used Stormbreaker to open a portal, thereby sending the threatening cosmic object barreling into some other part of the galaxy.

It was once split in half

Thor - Secret Invasion

Because it is made of Uru, Stormbreaker is highly resistant to destruction. It is not, however, indestructible. Under the right circumstances, it can reveal its own vulnerabilities.

In the Secret Invasion: Thor series, Beta Ray Bill ends up as a prisoner of the Skrulls, the extraterrestrials known for their ability to shapeshift. They send Bill to Asgard, where he is instructed to warn everyone of impending invasion. Thor suspects that Bill might actually be a Skrull in disguise. As a test, he throws Mjolnir to Bill. When he is worthy enough to catch it, Thor knows his identity is legitimate. The two band together to prepare for a fight against the Skrulls.

When the invasion happens, Bill comes face-to-face with an immense female warrior. She has his Stormbreaker, taken when he was held captive, which has been split in half. Despite not being in its original condition, the hammer retains its value, and the warrior quickly overpowers Bill. At this point, Thor intervenes and fights the Skrull. To match his strength, the warrior fuses Stormbreaker back into one. She tosses it. Thor catches the hammer and returns it to Bill.

This incident is noteworthy because it shows that Stormbreaker can be damaged, but also because it shows that, even in a compromised state, it is still a force to be reckoned with.

Transformation powers

Beta Ray Bill holding Stormbreaker

One of Stormbreaker's more unusual features is its transformation ability. To best see that in action, we need to look at its original owner, Beta Ray Bill. He's a Korbinite – one of a class of beings who moved from planet to planet, colonizing them through peaceful means. The planets they inhabited were destroyed when the demon Surtur unleashed a cosmic attack.

Later, Beta Ray Bill made his way to Earth, where he inhabited the body of a veteran. In this guise, he was known by the name “Simon Walters.” Whenever he wanted or needed to revert back to his Korbinite body, he could do so by tapping on Stormbreaker. The weapon allowed him to go back and forth between these identities.

At another point in his history, Bill had his consciousness transferred into a cyborg body. Similarly, he could transform back into his non-cyborg form by tapping Stormbreaker on the ground.

Stormbreaker proved vital to Bill throughout his comic book appearances, providing him with him a swift, efficient means of becoming whichever version of himself he wanted to be.

The appearance of Stormbreaker in Avengers: Infinity War suggests that Beta Ray Bill may show up in an MCU movie somewhere down the line.