Mega oboma in the room

Abomasnow-Mega @ Abomasite
Ability: Snow Warning
EVs: 4 HP / 252 Atk / 252 SpA
Quiet Nature
IVs: 0 Spe
- Blizzard
- Ice Shard
- Wood Hammer
- Earthquake

Cresselia @ Mental Herb
Ability: Levitate
EVs: 248 HP / 72 Def / 188 SpA
Bold Nature
IVs: 0 Atk
- Trick Room
- Lunar Dance
- Ice Beam
- Psychic

Marowak-Alola @ Thick Club
Ability: Lightning Rod
EVs: 252 HP / 252 Atk
Adamant Nature
IVs: 0 Spe
- Flare Blitz
- Shadow Bone
- Bonemerang
- Stealth Rock

Cofagrigus @ Leftovers
Ability: Mummy
EVs: 252 HP / 12 Def / 244 SpA
Bold Nature
IVs: 0 Atk
- Nasty Plot
- Trick Room
- Will-O-Wisp
- Shadow Ball

Crawdaunt @ Life Orb
Ability: Adaptability
EVs: 248 HP / 252 Atk / 8 SpD
Brave Nature
- Swords Dance
- Crabhammer
- Knock Off
- Aqua Jet

Magearna @ Fightinium Z
Ability: Soul-Heart
EVs: 252 HP / 248 SpA / 4 SpD
Quiet Nature
IVs: 0 Atk / 0 Spe
- Thunderbolt
- Ice Beam
- Focus Blast
- Trick Room