I got my first pranked toilet today! I'm so excited! I had no idea there was going to be pink smoke!!!
https://i.ibb.co/fMw2jMQ/pranked-toilet-cropped.png
I didn't see who did it, but the most likely culprit is the ghost mopping the floor, Cameron Fletcher. He is a goofball.
This is on maybe the fifth sim-day since the patch. Sounds like he took longer than most of your goofballs to try this?
On the other hand, since he's a ghost, he spends a lot of his day breaking plumbing under normal circumstances.