For the whole group. One by one each student comes up with an action and catchphrase for their “Superhero” It can be anything no matter how esoteric. “I like knives!” “Aldi Time!” “No sir, I think you’re mistaken”. After each student does their catchphrase, the whole group copies. When everyone is done, students can randomly do someone elses catchphrase (with action) and that will “pass” it to that person who has to do someone elses. It’s important you tell students to pay attention! (they are easy to forget sometimes)
Part 2. Now each student can come up with the supervillan version of their catchphrase, for the ones before it could be “Ooo you stabbed me!” “Direct from the farm” “Yes! Yes! Yes!”. Now when everyone’s done you can use either of the 2 catchphrases.