D/D/D Rebel King Leonidas (MP23-EN277) - 25th Anniversary Tin: Dueling Heroes Mega Pack 1st Edition

Pendulum Effect
When you take effect damage (except during the Damage Step): You can destroy this card, and if you do, any effect that would inflict damage to a player this turn increases their LP by the same amount, instead.
Monster Effect
When you take effect damage (except during the Damage Step): You can Special Summon this card from your hand, and if you do, gain LP equal to the damage you took. You take no effect damage.