RMT / Team Help Doubles Team help

[Skyshaymin]

Spoiler: Doubles OU team

Muk-Alola @ Black Sludge
Ability: Power of Alchemy
EVs: 252 HP / 252 Atk / 4 Spe
Adamant Nature
- Gunk Shot
- Shadow Sneak
- Knock Off
- Protect

Azumarill @ Sitrus Berry
Ability: Huge Power
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Aqua Jet
- Play Rough
- Superpower
- Belly Drum

Alakazam-Mega @ Alakazite
Ability: Synchronize
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
IVs: 0 Atk
- Psyshock
- Dazzling Gleam
- Shadow Ball
- Focus Blast

Chansey @ Eviolite
Ability: Natural Cure
EVs: 248 HP / 252 Def / 8 SpD
Bold Nature
IVs: 0 Atk
- Aromatherapy
- Soft-Boiled
- Seismic Toss
- Toxic

Goodra @ Assault Vest
Ability: Sap Sipper
EVs: 248 HP / 252 SpA / 8 SpD
Modest Nature
IVs: 0 Atk
- Draco Meteor
- Thunderbolt
- Fire Blast
- Sludge Wave

I've been testing this team out on showdown and it works pretty well, but I need a last pokemon to put in it. (Also it wasn't this exact team, I swapped an espeon for alakazam and edited some movesets) any ideas, and any mons I should replace?

 

[Mr. Kream]

Your Muk looks fun alongside Azu and Zam, and you're capable of some serious special walling with that team. Maybe too much, why not try something else over Chansey, like Magearna, it should play with the same incentives as your Muk and might be a good fit for you. Other than that, I think your Zam and Azu are safer running Protect.

For your last mon, why not pick something with another powerful ability that would benefit your Muk's Power of Alchemy? Something like Beast Boost or Defiant.