Guillotine inflicts damage equal to the target's current HP. Guillotine will break a Substitute on contact, and can be countered for infinite damage on the turn it breaks a Substitute.
Guillotine will not affect an opponent whose current Speed stat is greater than the user's current Speed stat.
Generation II and on
Unlike in Generation I, Guillotine can affect a Pokémon whose Speed stat is greater than the user's current Speed stat. However, it cannot affect a Pokémon of a higher level.
Gligar's claws glow white and it strikes the opponent with it, or Gligar grabs the opponent by the neck with a glowing white claw and slams it into the ground.