Go to the tech department with a banana. Say you would like to upgrade to an Apple.
Get an orange and throw it at a random person and yell, "Go, Pikachu!"
Run through the supermarket yelling "THEY'RE COMING" and see how many people start running with you.
Dress up as a mermaid, go to the seafood section, and start crying.
Scream at the grapes, throw them on the floor, and calmly walk away.
Yell at a bag of potatoes "YOU RUINED MY LIFE!"
Attempt to buy one grape.
Dress up as Pac-Man, have your friends dress up as the ghosts, and play a game in the aisles.
Hide in a wardrobe in the furniture section. When someone comes by, jump out and yell "WELCOME TO NARNIA."
In the pet section, point at a person and say, "I want that one."
Dress up as a teddy bear, sit in the toy section, and when someone walks by, say "PICK ME"
*drops mic and walks off stage*