Hmm. Time for another opinion that's probably going to be decisively shat on, but fk it.
Sableye for A-Rank.
Sableye is categorically the best Prankster in the entire tier, the only other one even able to use it is Tornadus, whose limited non-offensive movepool really allows it to do little else than Tailwind/Taunt/T-Wave. More importantly, Sableye can shut down entire stall teams solely by itself. I literally would have to have thousands of hands sprouting out of my body to be able to count the number of times on my fingers that I haven't switched from Sableye the whole match against a stall team, usually leading to a forfeit by T15. Priority Taunt by itself is ridiculously good, but when you combine it with reliable recovery, status, and a sick defensive typing it can become a seriously A-level threat.
For the purposes of argument, I'm going to talk about the SpD sableye set, which is arguably the best set.
Sableye @ Leftovers/Lagging Tail
Prankster
Careful Nature - 248 HP/252 SpD/8 Spe - 0 Speed IV
- Night Shade
- Will-O-Wisp/ Trick
- Taunt/ Trick
- Recover
Pros:
+ Prankster Taunt offers early game Hazard stopping as well as making Sableye immune to status unless switching in.
+ Priority Will-o-Wisp provides inherited physical bulk, theoretically bringing Sableye's defenses to 50/150/65.
+ Dark/Ghost defensive typing makes it immune to Normal/Fighting/Psychic as well as weak to literally nothing.
+ Access to Trick lets it emergency-cripple sweepers if the team has no surviving counter.
+ Access to reliable recovery in Recover, which is also priority.
+ Night Shade/Foul Play allows for decent solid damage allowing to kill off things like Roserade/Umbreon while blocking them from healing.
+ Access to other niche moves like priority weather set-up that can provide utility and team support, as well as weather-dependent options like Moonlight
Cons:
- Even with max SpD and inherited WoW bulk, it's by no means a defensive monster and can't be switched in on any powerful hits, with a few exceptions (Overheat/Leaf Storm without Hazard support can be tanked and then recovered off).
- Has little to no offensive presence other than reliable 100 HP damage. Has good offensive movepool with access to Sucker Punch, Zen Headbutt, Hone Claws, Foul Play, Shadow Claw/Ball, etc. etc. but can't back it up with 75 Att/65 SpA.
- Is relatively predictable given that the only viable set is support Prankster.