- Prevents flinching.
- Pokémon's accuracy cannot be lowered. Decreases wild encounter rate.
Level 100 Statistics (see level 5, 50, 100)
Sneasel shouldn't be considered bad at all. Its limited movepool, terrible defensive stats, and no STAB attacks to work with is what overshadows it, sadly. Focus more on its versatile physical offense. It will be a beast if it's set up. It destroys all Psychic- and Ghost-types not named Alakazam and Starmie. Well maybe those two withstanding their moves, but once set up, it can take them out.
It is just so hard for Sneasel to work its moves without STAB, especially when its movepool is limited. Just go with the move you need, like for example if you need to take down Substitute + Reversal Pokémon / Pokémon with Endure, you'll need Quick Attack, or if you want to cover weakness, go with Brick Break.
Choice Band set. I guess you can label it decent, especially since Fake Out makes Sneasel a UU Medicham.
Substitute + Focus Punch set and you could maybe Psych Up some fun stuff here. Still, its defenses are not a walk in the park.
Like Psych Up, Snatch can come in handy, but its defenses ruin it. Double-Edge and Iron Tail are there for the terrible lack of offensive moves. Seriously, if it can learn Surf, can it just learn a more valuable move? Protect just to prolong the battle. Taunt to shut down Dusclops guaranteed.
You can always give it the usual 4 HP / 252 Atk / 252 Spe spread. Not much to say for Sneasel as far as Sneasel's EVs are concerned. Just try to match Raikou and Starmie and whatnot. It's not like Special Attack will benefit in the battle. It should always be either Adamant or Jolly.
Checks and Counters
In Underused matches Sneasel is a dangerous foe, in order to beat it you will have to rely on prediction because if you let Sneasel in on your team, it will hurt you. Sneasel's problem is its lack of STAB moves, so Pokémon such as Granbull and other Intimidators (Arbok) will slow Sneasel down, Blastoise and Meganium can take hits from Sneasel, and Golem easily takes most of Sneasel's attacks and can beat it without any major troubles at all. Sudowoodo will hurt Sneasel too. Primeape's Cross Chop can really hurt Sneasel, but it won't switch in, being fragile. Same goes for Golduck, Magmar and Electabuzz.