E1 and regeneration

[rarehuntertay]

I have  {Experiment One} with 2 counters. I block a bigger creature. Can I remove the counters after damage to regenerate it?

[Yugornot]

No. Regeneration says "the next time this creature would be destroyed this turn". So the creature you're blocking would take one damage from you.

[Pleeb]

Yugornot is correct. Consider regeneration a force field vs destruction. If an arrow is going to kill you, it does no good to put up the shield after it hits. It has to be up before damage is assigned and state based effects are checked.

[Steerpike]

So basically right as you declare it a blocker, pay for the ability before passing priority

[Pleeb]

Pay for the ability any time before damage is delt.

[Birdbrain]

You can regenerate in response to your creature about to take damage

[Rass]

Good to know. I always thought you regenerated a creature after it took  lethal damage.

[Kaleo42]

That mistake made someone lose a pro tour game this season. He tried to regenerate too late.

[Orzhov and gruul]

What? But I thought that the regenerated creature can still deal damage to the other creature ( unless first strike ) even though it was removed from combat?

[griffin131]

You can (and do) since damage is applied simultaneously.
The issue here is that {Experiment One} requires you to remove 2 +1/+1 counters to regenerate. Doing this must be done before damage is done, so he only deals 1 damage at the damage step.

[Orzhov and gruul]

Oh okay so it only resolves the damage legally after regenerating

[griffin131]

You give the E1 the regeneration "buff" then damage is dealt. E1 would normally go to the graveyard but that action is replaced with tapping, etc.

[Orzhov and gruul]

So more or less thats how it works, then it would be better regenerating
Through attacking as it is already tapped. However I think that is not the point for {dutiful thrull} is definitely for block big fat creatures...(without trample)