Super Vivi!

Vivi (handing me a blanket): "I want you help me tie it on."

Me: Where?  Around your waist?

Vivi: No, Super Vivi!

Me: Um, around your neck? Like a cape?

Vivi: Yes, Mom.

(I tie it on and she runs into the bedroom where she can see herself in the full-length mirror.)

Vivi (from the bedroom): Super Viviiiiii!  Suuuuuuper Viviiiiii!

Our best guess is that this is a game she learned at a friend's house last night because it was completely new to us.