Not really anything gimmicky or outside the box but this is something I'm personally using and it does its job pretty damn well.
Houndoom (M) @ Life Orb
Trait: Flash Fire
EVs: 252 Spd / 252 Atk / 4 SAtk
- Fire Blast
- Sucker Punch
This set is amazing at handling Psychic and Ghost types, as these two groups of pokemon are most often the ones I want to remove from the game ASAP. Reason? To get rid of Spinblockers to keep my Crobat healthy and to eliminate a big portion of Fighting resists in the tier to open a path for Scarf Mienshao in the late game.
Yes, other Pokemon (especially Snorlax) can do the same without being as bulky as a Caterpie but those lack something very fundamental: The ability to not giving a F*** about Sableye (and Will-o-Wisp in general).
This set does not work on every team trying to facilitate a Fighting sweep though, as Houndoom requires a very well thought out team composition to effectively do its job. BUT what it does for my team is pretty damn amazing, considering the fact that Houndoom can't really fill that many niches in the UU tier.
After getting it in safely on a Psychic or Ghost Pokemon, you have the choice of either Crunch, Pursuit or Sucker Punch.
: If the opposing Pokemon is Slower than Houndoom, this is a solid way to deal damage, as some may fear Pursuit and go straight for an attack. Most of the time you won't need it for trapping.
: The standard trapping move, STAB + LO + 252Atk are usually enough to kill any Psychic or Ghost on their way out, with exceptions being really bulky things at full HP (Cresselia, Dusclops and Cofagrigus)
: Ghosts and Psychics fearing Pursuit might want to just attack right away, only to get killed beforehand by STAB Sucker Punch.
One very nice perk about this Houndoom its ability to completely ignore Sableye, one of the most annoying Pokemon in the entire game. Bait the Will-o-Wisp with Mienshao or Crobat, switch into Houndoom to get a Flash Fire boost, proceed to roast. 4SAtk LO Flash Fire Fire Blast will cleanly OHKO standard Sableye, while a switch into a bulky Water will only result in getting me a free switch into LO Shaymin.
I run 1 Fire STAB and a whooping 3 Dark STABs on this set, this Houndoom is not supposed to sweep, nor is it supposed to punch holes in my opponent's defenses. Its sole purpose is to remove anything that might wall Mienshao, especially Ghost types. Also, the high-powered Sucker Punch is very useful to finish off faster threats.
As I said, not anything really gimmicky or new, but it works wonderfully on my team. Part of its success so far (I peaked the UU ladder on Showdown at #7 not too long ago) is probably also thanks to the fact that people don't seem to know what to expect from a Houndoom as it is very underused (pun not intended).