MTG Salvation

Hi, my opponent cast a Spike Feeder, remove a counter from it to gain 2 life. I respond with skullcrack. Opponent responds to skullcrack by remove another counter from feeder. How much life do my opponent gain?

Assuming all the spells and abilities in this scenario resolve:

Here, 2 life. That's because activating Spike Feeder's last ability in response to Skullcrack will put that ability above Skullcrack and resolve before it. Then, once Skullcrack resolves players can't gain life this turn (among other things), so that the other Spike Feeder ability will do nothing when it resolves.

Note that only a +1/+1 counter (not a counter of some other kind) can be removed from Spike Feeder to pay for its last ability.

thanks for the clarification.