there is one, but he's rebattleable. If you go and use rock climb a few times(this is Route 226, to the right of the survival area) there are two trainers facing each other vertically on a high portion of the rock climb area. The bottom one isn't "wandering" per say, but its movements DO affect the RNG, as they are randomly switching between facing left and facing up. if you use the VS seeker though, he's no problem :)