I'll show you something amazing!

In the Korean comments

One comment reads, in translation, “Are you saying you’ll show us magic, or that you’ll scam us?” It jokingly recasts the trick’s deception as an attempted con.

What the words mean

얍 (yap, “hiya!”) has no literal propositional meaning. Here it works like “ta-da!” before the reveal, giving the title a casual, playfully theatrical register.