One recurring joke in powerful hero Shazam, the film was able to inject humor and a slightly more light-hearted tone into the franchise, which was especially important after criticisms that the DCEU was too dark and gritty.
Shazam! serves as an origin story for the titular hero in the DCEU, and as a result, much of the film focuses on Batson learning to manage his new dual identity. After discovering his powers, he begins searching for a superhero name, and it's a running joke in the movie that Billy finds it difficult to decide on a definitive moniker for his alter-ego. One of the many names given to Shazam when he starts trending online is "Zap-tain America", a name that's repeated once or twice throughout the movie. It's an obvious nod to Marvel's Captain America, taking Shazam's lightning powers into in service of the pun.
The use of the pun seemingly makes Captain America canon within the DCEU, despite the fact that he's never been mentioned before. Though he may simply exist as a fictional character in the franchise, the idea that the DCEU features both very real, tangible heroes and then separate, fictional ones is a little jarring. It also begs the question of which other Marvel characters exist within the DCEU, and why it hasn't come up more frequently (particularly as the franchise's stories are superhero-centric).
Though it's little more than a throwaway line, there's no mistaking the intention of the joke. The "America" part of the pun makes no sense in any other context, and therefore the characters of Shazam! are aware of Captain America's existence. It's not unlike Eternals' Superman reference, which also creates a strange and unnecessary issue regarding how and why Marvel and DC keep referencing their rivals' heroes in their respective movies. There's seemingly no animosity in the references, but the lack of any elaboration is a glaring and nagging inconsistency that makes the joke distinctly unfunny.
Though the joke regarding Shazam's inability to choose a name serves as a subtle reference to the character's real-life name change, the use of a Captain America pun was entirely unnecessary. By dropping a nod to a Marvel hero, Shazam! seemingly confirmed Marvel's existence within the DCEU's canon, and it did so without any additional context or explanation. The worst part is perhaps that the joke doesn't even really make sense on any other level, making Shazam!'s Captain America reference nothing but a vaguely confusing and ultimately pointless inclusion.
