Galarian Stunkfisk
Pros:
+Ground/Steel comes with a lot of resistances and 2 useful immunities, allowing it to switch in on stealth rocks and toxic spikes with little to no fear
+109/99/84 is pretty bulky
+Decent support movepool with options like stealth rocks, yawn, thunder wave and pain split
+Unique trapping move in Snap trap is a Grass-type clamp which is neat and I didnt even know existed until writing this
Cons:
-Mimicry is a new ability that changes type to match the current terrain (electric terrain, misty terrain, etc.). While interesting, it takes away Stunfisks many resistances and immunities, and with all the max moves changing terrain 24/7, its surprisingly difficult to control this ability
-poor offensive stats of 81/66/32 render it unable to utilize its offensive movepool
-ground/steel brings some key weaknesses to fire, water, fighting and ground
-excadrill has the same typing and fantastic stats, giving stunfisk no real niche
VGC
Ability: Mimicry
Nature: Impish/Bold
Ev's: 252 HP/252Def/4Spdef
Item: Leftovers
Moves: -Yawn
-Pain Split
-Earthquake/Foul Play/Snap trap
-Protect
Stunfisk I would imagine functions like a budget Hippowdon, just sitting around as a big fat pain in the ass that spams yawn all day. Unlike Hippowdon however, Stunkfisk has no real ability and no reliable recovery, outside of leftovers or pain split. It does get access to foul play however, allowing it to potentially threaten huge set up sweepers like snorlax or mudsdale. It also gets access to Snap trap, allowing it to keep something from switching and force it to sleep with yawn, temporarily forcing your opponent into a 1v2 situation.
There's no real point in discussing regular stunfisk since it's unavailable at the time of writing, and even though pokemon home launches later this month let's be real; regular stunfisk is pretty garbo too.