A player asked me this last night and, while I did some research to help obtain an answer, I would like an official answer so if I'm wrong I can correct myself.
Anthony, Natalie, and Nephalia are playing a game of Commander. Anthony uses the ability of
Sen Triplets to cast
Mind Control from Nephalia's hand targeting Natalie's
Avacyn, Angel of Hope, which is Natalie's Commander.
Anthony later loses the game while Natalie and Nehaplia are still actively playing, still in control of both the
Mind Control and
Avacyn, Angel of Hope.
The question was, what happens to those two cards not owned by Anthony.
I found CR 800.4a, which I referenced in giving my answer.
Originally posted by CR 800.4a:
When a player leaves the game, all objects (see rule 109) owned by that player leave the game and any effects which give that player control of any objects or players end. Then, if that player controlled any objects on the stack not represented by cards, those objects cease to exist. Then, if there are any objects still controlled by that player, those objects are exiled. This is not a state-based action. It happens as soon as the player leaves the game. If the player who left the game had priority at the time he or she left, priority passes to the next player in turn order who’s still in the game.
Mind Control and
Avacyn, Angel of Hope are objects that are not owned by Anthony, so they do not leave the game.
Mind Control generates a continuous effect that is applying in Layer 2. Is this an effect that gives Anthony control of an object, and therefore ends at this point, returning control of
Avacyn, Angel of Hope to Natalie? Or, as it is a continuous effect generated by the static ability of an object, does it remain in effect as long as
Mind Control is still on the field due to 611.3b?
CR 611.3b
The effect applies at all times that the permanent generating it is on the battlefield or the object generating it is in the appropriate zone.
Basically the question is if
Avacyn, Angel of Hope is exiled along with
Mind Control when Anthony leaves the game, or if
Avacyn, Angel of Hope returns to Natalie's control and only
Mind Control is exiled?
The way I read the rules, both
Avacyn, Angel of Hope and
Mind Control should be exiled when Anthony leaves the game, and Natalie has the option of replacing the exile event on
Avacyn, Angel of Hope and putting the card in her command zone per CR 903.12.