Spikes (=まきびしCaltrop) is a Ground-type move introduced in Generation II.
The user lays a trap of spikes at the foe's feet. The trap hurts foes that switch into battle.
Starting from Generation III, Spikes can be set up to three times. One layer of spikes will damage the opponent by 12.5% of its maximum HP, two layers by 18.75, and three layers by 25%. Flying-type Pokémon and Pokémon with Levitate are unaffected unless Gravity is used. Pokémon with Magic Guard are also unaffected. Rapid Spin and Defog remove the effects of Spikes. Rapid Spin removes Spikes from the user's side of the field, while Defog removes Spikes from the opponent's side of the field.