Before I begin, I would ike to say that Stunfisk has pretty much no use that another Pokémon can't do better. Landorus-I and Thundurus-T are both vastly superior Special attackers, while Milotic does better bulky speed control and Raikou has more bulk. But since you said you like to troll around…
You want troll? I'll give you troll m8.
You want to Assault Vest troll some n00bs? Then get rekt ready for Assault Vest Trollfisk.
360noscope (Stunfisk)@ Assault Vest
EVs: 252 HP / 252 Def / 4 SpD
- Earth Power
- Spite Scald
Here's the ultimate test of you Pokémon skillz, competitive Stunfisk. Assault Vest lets you tank hits4dayz. Static is the ultimate troll ability. Imagine a Mega Metagross giving your team trouble. You switch Stunfisk into Iron Head and boom! Get rekt by paralysis m8. The EVs and nature buff Stunfisk's lower defence, while AV boosts his respectabe Sp. Defence. Earth Power is Ground STAB, with that tiny chance to lower Sp. Defence and let you get one last quickscope in. Discharge essentially doubles your chance to paralyze Physical attackers.
Now we get to the good stuff. Scald is that cheap move that has a 30% chance to Burn. If you put together all of Stunfisk's abilities to inflict status, you get 90% (30% Discharge, 30% Static and 30% Scald). That's what I like to call
Finally, for the grand finale, we have ragequit Fissure. Open scenario:
>It's team deathmatch. Your team is down five members and so is theirs. It's winner-takes-all. You're at 5% HP and they're full. He's Paralyzed, so you'll move first. Despite that, you know you'll never KO him. And he knows it too. He selects his weapon of choice, dropping down for the kill and the win.
>Imagine the shock on his face when you noscope that scrub with Fissure.
Yep, that's about it for Stunfisk. He has a very small, amusing role to play competitively and makes a good troll, but other than that he's pretty trashy.