Oh, that is right about Aurorus. I forgot about that one. And what I mean about being able to function in any tier means that Prankster Pokemon can typically still do things with the right switch-in. M Meowstic can dismantle a lot of Pokemon reliably with Trick and Skill Swap, Steal boosts with Snatch, setup Trick Room without negatively impacting himself, Thunder Wave any non-electric or ground type without fear of being out-sped, or use Psych Up on a Pokemon who's been setting up on you. You can get things done without needing support from other Pokemon, unlike say Rapidash who struggles to OHKO a lot of threats not weak to Fire and typically KOs herself with recoil and low HP. There is a reason why he's untiered for sure, but there are Pokemon in lower tiers, even untiered Pokemon, who can still put in work. You typically just need to be creative, unless you're literally going to tournaments with people who will be just as skilled, if not more skilled, than yourself.