I don't know if this might link to Missingno., but today I was playing my XD and when I was going to fight a Cipher Peon at Phenac city my game went nuts. It said I sent out ? and Gardevour but the pokemon weren't there! The ? was my Donphan with all the same attacks and everything. I was so freaked out. So after using one attack from Gardevour, the pokemon appeared! Then I used an attack with the ? and after the attack, Donphan appeared. It didn't say ? anymore so I was relieved. The strangest part is, my character looked up at the sky as if the pokemon was like 10 ft tall! So maybe this story could be related to missingno. Thought it would be good to know.