Spirit Link

Oracle Text

Enchant creature (Target a creature as you cast this. This card enters the battlefield attached to that creature.)

Whenever enchanted creature deals damage, you gain that much life.

Card Rulings

10/4/2004 You only gain the life when the triggered ability resolves. If you are reduced to zero life before the ability resolves, you will lose before gaining the life.
4/1/2008 You gain life for all damage which is not prevented, regardless of what the creature damages (player or another creature) or the toughness of the blocking creature. If you put this on a 5/5 and it is blocked by a 1/1, you still gain 5 life.