One of my favorite troll techniques, the following works very well for sweeping teams, and will almost always make your opponent feel stupid.
EVs: 252 special attack, 252 speed, 4 HP
Nasty plot (boosts for sweeping)
Dark pulse (STAB, more reliable than night daze)
Hidden power ice (coverage)
The trick here is that you set up your team so that zoroark will be disguised as a Toxicroak, which is pretty much the perfect pokemon for zoroark to look like. With toxicroak's 4X weakness to psychic, and zoroark's immunity to it, you are often able to set up with nasty plot and use dark pulse to belt the fool who switched in with a psychic type. Also, HP ice covers all of toxicroak's non-psychic weaknesses, effectively murdering anything that switches in on zoroark for what they believe is a type advantage. One more thing that makes this strategy ruthless is that Toxicroak can learn all of the moves in this set, leaving less suspicion as to whether it is an actual Toxicroak.