In battle
Stall causes a Pokémon with this Ability to move last within its priority bracket. Therefore, a Pokémon with this Ability will move after other Pokémon using moves with the same or higher priority during a turn of a battle. Increased priority moves will always go first, whether or not the move is used by the Pokémon with Stall. If another Pokémon uses a decreased priority move, it will go after the Pokémon with Stall.
Pokémon holding the items Lagging Tail or Full Incense will move after a Pokémon with Stall, assuming they use moves of the same priority. If a Pokémon with Stall holds Lagging Tail or Full Incense, the item takes effect and Stall is ignored. The item Quick Claw can also still activate when held by a Pokémon with Stall and causes the Pokémon to move first, overriding Stall.
Stall's effect is not affected by Trick Room.
When two Pokémon with Stall are in the same battle and use moves in the same priority bracket, the Pokémon with the lower Speed stat will move first.
Outside of battle
Stall has no effect outside of battle.
A Pokémon with Stall only attacks foes that are directly in front of them. This does not affect leaders.