Mega Steelix
i agree with FV here, it's really good at what it does, very splashable on like every team and much more. I think Mega Steelix should be higher than mola IMO.
This is definitely a biased nomination because Abomasnow was one of my favorite and most used 'mons back when I played this tier actively, but I just feel like this Pokemon shaped the metagame in a pretty interesting way that no other offensive Pokemon in RU (aside from Moltres, obviously) was able to. My favorite example of that is how it stopped Alomomola + Mega Steelix balance (which ended up becoming the dominant playstyle after MEGA BIG CHILL's ban) cold.Mega Abomasnow
I can respect bringing up Alomomola as a top 3 Pokemon, butAbomasnow was massive, both in XY (I mean, aside from Banette, which was underwhelming most of the time, Abomasnow was pretty much the Mega Evolution of RU) and when it finally dropped again in ORAS, getting banned eventually mainly due to the fact that most of its reliable checks, such as Moltres, Doublade and Cobalion, weren't really in the tier any more.