Rotom-Heat @ Firium Z  
Ability: Levitate  
Level: 50  
EVs: 252 HP / 60 Def / 196 SpA  
Modest Nature  
IVs: 0 Atk  
- Thunderbolt  
- Nasty Plot  
- Overheat  
- Protect

Unown
Options:
- offensive: Hidden Power Ice
- supportive: Will-O-Wisp, Ally Switch, Electroweb
- items: Safety Goggles, Sitrus Berry, Wiki Berry

Unown
Offensive calcs:
- 196+ SpA Rotom-H Inferno Overdrive (195 BP) vs. 252 HP / 4 SpD Glastrier: 278-330 (134.2 - 159.4%) -- guaranteed OHKO
- 196+ SpA Rotom-H Inferno Overdrive (195 BP) vs. 4 HP / 0 SpD Landorus-T: 181-214 (109.6 - 129.6%) -- guaranteed OHKO
- 196+ SpA Rotom-H Inferno Overdrive (195 BP) vs. 252 HP / 4 SpD Aegislash-Shield: 224-266 (134.1 - 159.2%) -- guaranteed OHKO
- 196+ SpA Rotom-H Overheat vs. 4 HP / 0 SpD Mega Metagross: 186-222 (119.2 - 142.3%) -- guaranteed OHKO
- 196+ SpA Rotom-H Thunderbolt vs. 0 HP / 4 SpD Mega Hawlucha: 152-182 (99.3 - 118.9%) -- 93.8% chance to OHKO
- 196+ SpA Rotom-H Thunderbolt vs. 252 HP / 72+ SpD Mega Slowking: 110-132 (54.4 - 65.3%) -- guaranteed 2HKO
Defensive calcs:
- 252+ Atk Landorus-T Rock Slide vs. 252 HP / 60 Def Rotom-H: 68-80 (43.3 - 50.9%) -- 2% chance to 2HKO

Unown
Useful partners:
- Pokémon to threaten Water: Rillaboom, Kartana, Tsareena
- Storm Drain: Gastrodon