Azrail93
It's a choice between Beldum and Gible for me, just for mega evolution access. And between those two, I would choose Gible, because if Mika wanted to catch a Beldum in the wild, I'm sure he would be able to at least have a proper negotiation with a Metagross protecting it, while on the other hand, a Garchomp would most likely try to kill him on sight.