Since this whole confusion chance thing seems to still be under debate, I've decided to start collecting my own data. These preliminary results unfortunately don't include data on the duration of confusion, but I'll start counting that from now on. I tested in the wild in an SOS chain of Oricorios while spamming Teeter Dance with a Tangled Feet Spinda, and in 212 attempts at making moves by confused Pokémon (including attempts to copy Teeter Dance by the Oricorio), 135 of the moves succeeded, while 77 resulted in a self-hit. This comes out to about a 36.32% chance to hit one's self in confusion, disregarding the turn a Pokémon snaps out. It's not a terribly large sample size, and again, I neglected to count the number of times a Pokémon snapped out of confusion, but as I was testing, the ratio seemed to stay around 40-60 of self-hits to successful moves through Confusion.
Also, I noticed some interesting mechanics with Dancer while collecting this data, though these may already be known.
- Attempting to use a move through Dancer while confused has to pass through the roll, same as any other move, and this also counts towards Confusion's duration counter.
- Dancer didn't copy Teeter Dance unless it successfully confused at least one Pokémon.
- For some reason, when there are two Pokémon on the field with Dancer, and a third Pokémon uses a dance move, the slower Pokémon with Dancer will copy the move first. At first, I thought it might've just been speed ties, but this was consistently the case, and I never noticed any two Oricorio actually tying. On a somewhat related note, Teeter Dance applied confusion in the same exact order every time, regardless of speed: ally first, then (the user's) right to left on the opponent's side.