I just came up with something really nasty for trrademarked. Behold my idea:
Get a mon to pass aurora veil (therefore, snow + veil), into CLOYSTER. You have it with trademark "iron defense". Now stupid calcs:
252+ Atk Protosynthesis Roaring Moon Crunch vs. +2 248 HP / 252+ Def Cloyster with an ally's Aurora Veil: 23-27 (7.5 - 8.9%) -- possibly the worst move ever
+6 252+ Atk Protosynthesis Roaring Moon Crunch vs. +2 248 HP / 252+ Def Cloyster with an ally's Aurora Veil: 92-108 (30.3 - 35.6%) -- 37.5% chance to 3HKO
And to bigger extremes:
+6 252+ Atk Choice Band Adaptability Tera Dark Roaring Moon Crunch vs. +2 248 HP / 252+ Def Cloyster with an ally's Aurora Veil: 158-188 (52.1 - 62%) -- guaranteed 2HKO
So that cloyster can take on even a hit from a +6 banded tera adaptability roaring moon.
This thing is not THAT bad offensively, but it can wield massive support moves, such a priority stab with shard, spikes, tspikes, trapping with whirlpool, aqua ring, rest... I would argue that after removing any special attackers, this setup is just GG.
Alternatively you can Twave in Offesne MUs to support Hoopa and Pult. I really like this bidirectional support. Twave also beats Slowking G, funnily enough.