The phrase comes from a Brazilian Portuguese dub of Batman, where Eu nao acredito translates as I can't believe it, but the exact scene is shared online without consistent sourcing. Clips like this spread on soundboards and in Brazilian meme edits because the line is short, clearly acted and understood even by viewers who do not speak Portuguese. It has become a reusable reaction for disbelief, passed between short videos, group chats and fan edits rather than tied to one specific release or moment in theatres.