a prank - A prank is when you say 'is this a joke?' to someone when so

A prank is when you say 'is this a joke?' to someone when something weird happens and you're trying to act cool.

I said 'is this a joke?' when my friend turned my phone into a banana.

I said 'is this a joke?' when my teacher made me wear a hat that said 'I love math.'

I said 'is this a joke?' when my little brother put glitter in my cereal.