Tarantulas: He went to the Unown event, and he's taken part in the current kidnapping as well. Beyond that, he's been picking off random NPCs around the Goldenrod area for their supplies and the like, aaaand let's not forget how he kidnapped + tortured Kay and Minnie Mouse each for about a week each.

As a "mysterious person", he also gave Cocona quite a beating with some Pokemon to scare the residents of Goldenrod! Not that anyone would actually know that. But it was still done!