See Jetstream Aeronaut. Included "may prevent that damage." I thought that the damage would be automatically prevented if you chose to sac the creature, but then I actually didn't know, so I made sure to include that clause. The sac should come with the damage prevention on the other cards.

That seems very powerful, esp if it has evasion

Reasonably poweful, I'd say, you sacrifice this creature and get some +1/+1 counters for a mana cost that might outright create those counters on other spells.

> I thought that the damage would be automatically prevented if you chose to sac the creature, but then I actually didn't know, so I made sure to include that clause.

Well, what would happen with regards to the damage would depent on what kind of ability this is. You don't seem to have decided between replacement effect and triggered ability based on the hybrid wording.

SecretInfiltrator: It's supposed to be a replacement effect on a trigger.

dude1818: The creature as-is has no evasion.

Technically, "when you would deal combat damage" doesn't make any sense, as far as the game is concerned. The trigger might go on the stack... but the damage would 'resolve' before the ability did.

I think Mindstab Thrull has a better template for what you're working with. Don't look at the image of the 5th edition card. It's current wording is:

"Whenever Mindstab Thrull attacks and isn't blocked, you may sacrifice it. If you do, defending player discards three cards."

Doesn't combo with trample like yours does... but I doubt you were going for that anyways.

WHat I omitted "when" entirely to make a replacement instead of trigger, but word the replacement so that the replacement is optional.

"If Feast's QUail would deal combat damage to a player you may prevent that damage. If you do,..."?

I think that's best