What it does
Mortal Spin is a Normal-type physical move with low base power and 100% accuracy. On hit, it clears all entry hazards (Stealth Rock, Spikes, Toxic Spikes, any combination) from your side of the field. It also has a chance to inflict regular poison on the target.
The hazard removal triggers when the move hits any opposing Pokémon. You don't need to target the Pokémon that set the hazards — landing the move on either opponent in doubles is enough to clear your side. That's useful: even in a situation where the setter is gone, the hazards remain until removed, and Mortal Spin clears all of them in one action.
The poison proc isn't guaranteed. Regular poison deals roughly 1/8 max HP per turn — meaningful on bulky targets over several turns, but it's a side benefit. You're clicking this for the hazard removal.
Critical weakness: Normal-type moves don't affect Ghost-types. If a Ghost-type is the only Pokémon left on the opposing side, Mortal Spin can't hit and therefore can't clear hazards. Opponents sometimes deliberately position Ghost-types to block spinning — factor this into game plan.
Who runs it
Glimmora at 23% usage is its primary competitive carrier. Glimmora is Rock/Poison-type with the ability Toxic Debris, which automatically sets up Toxic Spikes on the opponent's field whenever Glimmora is hit by a physical move. So it creates hazards while also being capable of removing your own. The tactical loop is self-contained: opponent attacks it physically, Toxic Spikes go up on their side; Glimmora can use Mortal Spin to clear whatever was laid on yours.
23% usage means this is a niche pick, not a cornerstone — but in hazard-focused teams, its dual role is specific and hard to replace with other options.
How to use it
Timing is the whole skill set here. Entry hazards only hurt when Pokémon switch in, so the optimal moment to clear is right before a key switch-in — not reflexively on the first turn hazards are set. If the hazards haven't triggered damage yet and you're not switching anyone in this turn, waiting is usually fine.
Glimmora's physical Attack is not high, so the actual damage from Mortal Spin is limited. Don't count on it as an offensive contribution — use it when the hazard removal is worth the action economy.
Tips & strategy
Ghost-type blocking is the main counterplay. If the opponent brings a Ghost-type specifically to wall your spinner, you either need to remove the Ghost-type first or accept that Mortal Spin won't clear. Having a Pokémon with a Ghost-coverage move as a backup is good team construction when you rely on hazard clearing.
Unlike Rapid Spin, which in singles also boosts Speed by one stage on use, Mortal Spin doesn't provide that Speed bonus. In doubles it's a smaller difference — hazard removal is the metric that matters for both moves.