Alright. I think this is one of the most common Spiritomb sets. It's been seen on numerous stall teams (most notably Obi's stall team) and I think it's definitely something that needs to be in any Spiritomb analysis.
[SET]
name: Rest / Sleep Talk
move 1: Shadow Ball
move 2: Hidden Power Fighting / Will-o-wisp
move 3: Rest
move 4: Sleep Talk
item: Leftovers
nature: Calm
evs: 252 HP / 96 Def / 160 SpD
[SET COMMENTS]
<p>Rest and Sleep Talk together work excellently on Spiritomb. With this set, he can absorb Gengar Hypnosis, making him a near-perfect switch-in to any Gengar. The recovery granted to him by Rest allows him to be an even more efficient counter to Gengar, Azelf, Lucario, and Deoxys-S. The aforementioned recovery allows him to stick around for much longer, serving as a useful blocker of Rapid Spin for a team.</p>
<p>Shadow Ball and Hidden Power Fighting are the primary options on this set, as together they are unresisted and allow for Super-Effective hits on most of the threats that Spiritomb seeks to counter. Hidden Power Fighting is what makes Spiritomb one of the best Lucario switch-ins, as he can take any one attack boosted by a Swords Dance or any two attacks boosted by Choice Specs. Another option is to run Will-o-wisp; Spiritomb still maintains the ability to hit Gengar, Azelf, and Deoxys-S Super Effectively and lets Spiritomb burn Lucario and the somewhat common Rapid Spinning Donphan. Shadow Ball / HP Fighting is more reliable, though, as nothing resists both and there are no accuracy issues to worry about.</p>
<p>The EVs are tailored to optimally counter Gengar. With this spread, Gengar's unboosted Shadow Ball is a 4HKO. This allows Spiritomb to beat Hypnosis / Substitute Gengar, as otherwise Gengar can kill Spiritomb before the Rest / Sleep Talk cycle ends, with Substitute guarding against the 33% chance of Shadow Ball being picked. The rest of the EVs are placed in Defense to better weather physical hits. If you want a bit more Defense 252 HP / 140 Def / 116 SpD and a Calm nature allow Spiritomb to survive any Salamence Draco Meteor.</p>