name: Sphail Stall
move 1: Substitute
move 2: Protect
move 3: Yawn
move 4: Blizzard / Toxic
ability: Ice Body
nature: Bold / Calm
evs: 36 Def / 236 SpA / 196 SpD
Spheal can utilize the Ice Body ability to the fullest extent in this set. Because of the lack of HP EVs, Spheal only gets to 23 HP at which substitutes only cost Spheal 5 HP. If it is hailing, then when Spheal uses Substitute, at the end of the turn Spheal gains 1 HP from leftovers and 1 more HP from Ice Body. The next turn, Spheal uses Protect, and at the end of the turn 2 more HP are gained, bringing Spheal’s HP back to only 1 below where it started. If your opponent is losing more than 1 HP per turn, Spheal can go through many members of the opponent’s team.
A few things need to happen before Spheal gets sent in. First, Snover needs to come in and set up perma-hail. Then, Toxic Spikes need to be set up. While two layers are nice, one layer of Toxic Spikes is enough for Spheal to work effectively. Without Toxic Spikes support, Pokemon holding Leftovers won't take hail damage, and Spheal will gradually lose 1 HP at a time until he faints.
Spheal is only effective if it has a substitute at the beginning of the turn. Once you have a substitute up, alternate between Protect and Substitute for the best stalling ability. If something comes in that is a Flying-type, a Steel-type, or a levitator and is not poisoned by the toxic spikes, you can hit it with STAB Blizzard, yawn it, or hit it with Toxic. If it is possible, use Yawn, because then Spheal will still have his substitute up at the end of two turns.
Spheal’s stats are placed defensively but his typing makes it weak to Fighting, Ground, Electric, Grass, and Rock, which makes him a poor choice for a defensive set or a Curse set. With a speed stat of 13 and no priority moves, it is outclassed offensively by many Pokemon such as Swinub and Snover, so his only real appeal is his Ice Body ability. As for other offensive options on the hail stall moveset, Spheal learns Surf and Earthquake, each of which can be used over Blizzard.
Never put any evs into HP, for reasons stated above. Maximize SpD and SpA, if you use Blizzard. Defense evs are largely useless because almost all physical attackers know a move of a type that Spheal is weak to; however, it can help Spheal switch in more safely.
It will be difficult, and in some matches impossible, to find a scenario where Spheal can get his initial substitute up. Spheal walls most Water-types, such as Squirtle and Wailmer, giving Spheal some opportunities to get that initial Substitute up. Although it can be fairly effective, it needs to have half of a team based around him. It needs Snover to set up perma-hail; it needs a toxic spiker, and even then, Spheal will have a hard time switching into almost anything and then surviving a hit from it with more than 25% so that it can get its initial substitute. It is usable and can devastate many teams in LC; it is just slightly impractical.
Since Spheal is difficult to stop once it gets a substitute up, in order to stop it you need to take away one of the components that make it work effectively. First, Spheal needs hail, so Hippopotas can come in on any move other than Blizzard and wreck Spheal’s chances of stalling. Any Poison-type switch in, such as Croagunk or Bellsprout, especially after the toxic spiker has fainted, ruins Spheal's productiveness. Users of Taunt can put Spheal in check, but have to be wary of Blizzard.