Don't mess around with other people's gadgets! Especially if you don't know what they do! Somebody should've told that to Deku when he found a suspicious tool in Tsuyu's room.
He was running a simple errand for her, and yet he somehow managed to get himself into more trouble than he bargained for. Luckily for him, it seems like the real Tsuyu likes the changes that happened to "Deku" and gives him a small taste of what it's like to be her.
Enjoy!~