How does regeneration work in Magic the Gathering?

Question

How does regeneration work?

I know that if my creature is destroyed then I can spend X mana then tap my creature and move it out of combat. Is it attackable in any way after that? With spells or instants?

If someone for example casts Shock on my Manor Skeleton, can I say in response “Ok, I will spend 2 mana to regenerate it”? Or does Shock immediately resolve to destroy the creature (assuming it has no regeneration shield on it)?

Answer 1

A creature is destroyed when a resolved spell or effect says so (destruction by effect), or when the total damage it received this turn from anywhere is equal to or greater than its current toughness (destruction by game rules).

At any time you can regenerate a creature with an appropriate spell or effect. The only condition is that the regeneration has to happen before the destruction effect. You can regenerate a creature as often as you like, anytime. For each time you regenerate it, the creature gets a "regeneration shield" that lasts until the turn ends or until it is used up by a destruction effect, whatever happens first. If a destruction event would happen and the creature has a "regeneration shield" active, the following things happen:

• One of those shields is removed
• All damage received by the creature this turn is removed
• If a destruction effect caused the event to trigger, it resolves but has no effect
• The creature gets tapped (Note that this is an effect of regeneration. The creature does not have to be untapped to regenerate it)
• The creature gets removed from combat, if it was regenerated during combat

Note that certain spells or effects state something like "Destroy target creature. It can't be regenerated.". In that case, you can still respond with a regeneration shield, but the regeneration effect is ignored and the creature still gets destroyed.

Is it attackable in any way after that? With spells or instants?

"Attack" has a defined meaning in M:TG: You attack with creatures only, during a combat phase. The only valid targets for an attack are opposing players and Planeswalkers. The correct term to use for spells and effects is "target", if it is a targeted spell or effect. And yes, regeneration provides no further protection from multiple damage sources or spells/effects. You can, as stated above, provide multiple regeneration shields, so as long as you can pay the costs, you can regenerate as often as you want.

Answer 2

Responding to your edit:

What I really wanted to know is that if someone uses for example Shock on my creature can I say at that moment "Ok, I will spend 2 mana and regenerate my creature" or when that Shock is played it is resolved immediately any my creature is destroyed (assuming that it has 1 toughness and no regeneration shield on it)

How the rules of Magic work is as follows:

Your opponent pays 1 red mana and casts Shock. Shock is now placed "on the stack". Assuming that neither you nor your opponent want to play any spells or abilities in response, Shock "resolves", your creature takes 2 damage, and, assuming its toughness is 2 or less, goes to the graveyard.

However, you do want to do something, which is regenerate your creature! With Shock on the stack, you say "in response, I regenerate" and pay your mana. This puts the ability on the stack, on top of Shock. Now, assuming neither you nor your opponent want to play any more spells or abilities, the objects on the stack start to resolve from top to bottom (LIFO), thus the ability resolves first and a regeneration shield is created. Now Shock is at the top of the stack; assuming neither you nor your opponent want to play any more spells or abilities, it resolves, and your creature is dealt 2 damage, though this time it survives thanks to the replacement effect provided by its regeneration shield.

Here's an interesting case for you: your opponent casts Shock on your creature. In response, you tap two lands, and use your creature's regeneration ability. In response to this, your opponent taps for another red mana and casts another Shock from his hand! You may at this point be out of mana and unable to respond by using the regeneration ability again. In this case your creature is toast, despite trying to regenerate, as the second Shock will resolve before anything else...

Hope this helps you visualise how the stack works - it's quite hard until you suddenly "get it", and then it's pretty easy, I promise you!

Answer 3

What I really wanted to know is that if someone uses for example Shock on my creature can I say at that moment "Ok, I will spend 2 mana and regenerate my creature"

Short answer: Yes.

Longer answer: I linked this nice article as a comment to your question that has a very thorough discussion, with examples, of how the Stack and Priority works in MtG. I thought I'd give the summary here. Note in this synopsis I will ignore any rules, cards or keywords that may modify these rules. (ie. Split Second, Flash)

1. When a player plays a spell or ability, that player keeps priority. The Spell/Ability is on the stack but doesn't resolve yet (ie. Shock).
2. When a player with priority passes priority with a Spell/Ability on the stack, the next player may play an Instant or activate an ability (ie. regenerate). If they do, it goes on the top of the stack but doesn't resolve yet.
3. The Spell/Ability on top of the stack resolves when both (or all, in multiplayer games) players pass priority in a row.
4. When a spell resolves, the active player (the player whose turn it is), gets priority. If there are still spells or abilities on the stack, go to step 2.

And just to be crystal clear, once the Regeneration Shield resolves (replaces a destruction effect) that card can still be targeted again. If your opponent has another Shock and has mana, he can cast the spell on your creature. Of course, if you still have the mana, you can regenerate it again…

Answer 4

The way regeneration works is that, when a creature is regenerated, it receives protection from the next effect that would put it into the graveyard equivalent to the "destroy" action. So, if your creature would receive lethal damage or be targeted by a Doom Blade or something, you can activate regeneration, and when the effect occurs, the destruction part of the effect is ignored, and instead the creature is tapped, if it wasn't already. (So a creature with lethal damage has the damage removed, but the creature remains in play.) The regeneration "shield" only protects against the first such effect; if your creature has two toughness and there are two Lightning Bolts on the stack targeting it, you'll need to activate its regeneration ability twice to keep it from dying. Regeneration also doesn't protect against effects that exile the creature, sacrifice effects, or effects that specify that the creature is destroyed and cannot be regenerated.