Here's the set I've been using. It looks pretty standard, until you realise I use both psyshock and psychic, and don't use trick at all.
Gothitelle @ Choice Specs
Ability: Shadow Tag
EVs: 4 Def / 252 SpA / 252 Spe
Modest Nature
IVs: 0 Atk
- Psychic
- Psyshock
- Energy Ball
- Thunderbolt
I ran trick originally, but found that simply locking a stall mon into a move while also losing my 1.5 boost just wasn't working. I also found myself having trouble differentiation between whether or not certain pokemon were defensive or specially defensive. The biggest example of this is Mega-Venu, who caught me off guard a few times due to its epic walling capabilities. Having both stabs allows me to break through defensive and specially defensive mons with my powerful attacks, with energy ball and thunderbolt allowing me to kill other things with some super-effective damage. Obviously, these last two moves can be played around with to suit the needs of your team, as this set is still walled by Heatran, Ferrothorn, and Scizor. All in all, despite forgoing the choice-locking power of trick, this Gothitelle set is highly effective at trapping and killing your opponent's stall mons.
Edit: Also, if someone wants to try out a competitive defog-blocker set, that'd be great
Edit 2: Like Aragorn the king said, if you want to hit Hippowdon and Suicune Harder, use Grass Knot > Energy Ball