Can you target a stunned unit with Facebreaker to trigger stun-related effects like Leona?

Question

Accepted Answer

You may choose a unit that is already Stunned as a target for Facebreaker, but choosing an already Stunned unit does not Stun it again — so it will not cause "when you stun..." triggers like Leona - Radiant Dawn to see a new stun on that unit. [423.1.a.1] [355.5]

You can target an already Stunned unit with Facebreaker, but nothing will reapply the Stunned state to that unit and it will not cause "When you stun one or more enemy units" triggers (e.g., Leona - Radiant Dawn) to trigger for that unit. To trigger such abilities, the spell must actually Stun at least one enemy unit that is not already Stunned. [423.1.a.1] [355.5]

You play Facebreaker and, as you finalize it on the chain, you choose a friendly unit and an enemy unit at the same battlefield as its targets (this is a Choice/Target selection). [355.5] [355.9.b] Those chosen units remain as the spell's targets on the chain even if their status changes while the spell is on the chain, provided they remain the same game objects on the Board. [359] [355.5] When Facebreaker resolves, the game will attempt to Stun each chosen unit. If a chosen unit is not currently Stunned, it becomes Stunned and this counts as Stun happening to that unit (which can satisfy "When you stun…" triggers). [423.1] If a chosen unit is already Stunned at resolution, it cannot be Stunned again — the Stunned state is not reapplied and no "when you stun…" trigger will be caused by that unit. The spell can still affect the other chosen unit if it was a legal target. [423.1.a.1] [355.9.b] Therefore, Leona - Radiant Dawn’s "When you stun one or more enemy units" will only trigger from Facebreaker if at least one enemy unit that was not already Stunned becomes Stunned by the resolving spell. [423.1.a.1]

If you choose an enemy unit as Facebreaker's target and then, before resolution, that unit is moved to a different zone off the board (e.g., to hand or trash), it ceases to be the same game object and will no longer be a target — the instruction to Stun it will be ignored for that target. In that case, whether Leona - Radiant Dawn triggers depends on whether any remaining target actually became Stunned. [359.3.e.4] [359.3.e.5] If you choose an enemy unit that's not stunned and an opponent reacts and Stuns that unit before Facebreaker resolves, then at resolution the unit is already Stunned and cannot be Stunned again, so Leona - Radiant Dawn would not see that unit being stunned by Facebreaker. You would need at least one enemy unit that is not stunned at resolution to become Stunned to trigger Radiant Dawn. [423.1.a.1] [359] If Facebreaker is played from Hidden, its targets must be chosen from units at that battlefield when finalized, per hidden rules. That doesn't change the above interaction — an already Stunned chosen unit still won't be Stunned again at resolution. [811.1.d.2] [423.1.a.1]

Short answer: Yes, you can choose an already Stunned unit as one of Facebreaker's targets when you finalize the spell, but choosing an already Stunned unit does not Stun it again and therefore will not create a new "when you stun…" event for that unit. When you play Facebreaker you make the target choices as you finalize the spell on the chain (these are Choices/Targets) [355.5] [355.9.b]. The rules explicitly state that a Stunned Unit cannot be Stunned again; you may choose a unit that's already Stunned, but nothing new happens to make it Stunned again and abilities that trigger "when you stun" won't see it as being stunned at resolution [423.1.a.1].

Concretely: if you play Facebreaker and its chosen enemy unit is not Stunned at resolution, that unit will become Stunned and that counts as "stunning" for purposes of triggers like Leona - Radiant Dawn's "When you stun one or more enemy units…". If the chosen enemy unit is already Stunned at resolution, it will remain Stunned but will not be Stunned again and so it will not cause Radiant Dawn's trigger to fire from that unit. For Radiant Dawn to trigger via Facebreaker, at least one enemy unit must actually become Stunned as the spell resolves. This behavior is consistent with the targeting/finalization rules and the rule that a Stunned Unit cannot be Stunned again [355.5] [423.1.a.1].

Additional notes: if a target changes zone off the board before resolution it ceases to be the same game object and will not be affected [359.3.e.4]. If Facebreaker is played from Hidden, you must choose targets from that battlefield when finalizing the spell, per Hidden rules, but that does not change the rule that you cannot Stun an already Stunned unit again [811.1.d.2] [423.1.a.1].