Superhero Underwear

I welcomed 4 year old Z into the school this morning.
Z: Good morning Teacher KC.
Me: Good morning, Z.
Z: Teacher, I've got new underwear today.
Me: Oh! Say byebye to papa.
Z: Bye papa.
Me: So you've got new underwear today. Are you wearing it?
Z: Yea. It's in here. (pointing at his pants)
Me: I see. Does it feel different?
Z: Ya. (Isn't it amazing how some kids always say "ya" to anything they don't understand?)
Me: Ooh~
Z: Ya. I'll show it to you later.
Me: Oh, ok. ... Really? Are you sure?
Z: Ya! It's superhero underwear!