>>25047070>>25047083uh, that's funny
Well, I did happen to get something similar, and I've seen other people having the same problem, but it was just some of the Pokémon sprites with some of the pixels out of place. And they did change like that. After defeating them they disappeared too. I don't think you should get worried too much, but I guess it would be interesting to find out how it happens. You happened to have a particularly cool result though.
I think the pink thing is supposed to be part of Cyndaquil's sprite. There was a Cyndaquil near to it and it was strange as well.