Does the Watcher ability affect all enemy units count as 'choosing' them for the purpose of triggering 'when chosen by enemy spells or abilities' effects?

Question

Accepted Answer

It depends on how the Watcher’s ability is worded. If the ability “chooses” units (uses “choose,” “choose any number,” or otherwise makes those unit choices as part of the spell/ability), those units are being targeted/“chosen” and will trigger effects that care about “when chosen by enemy spells or abilities.” If the ability instead affects “all enemy units” or otherwise programmatically selects units without a choice by the spell’s controller, it is not “choosing” them and will not trigger those “when chosen” effects.

If the Watcher ability explicitly chooses units (text contains a choose instruction), it creates a target relationship and counts as being chosen for triggers that care about “when chosen by enemy spells or abilities” [355.7] [355.9]. If the Watcher ability instead affects units by programmatic selection (e.g., “all enemy units” or “each enemy unit”), that is not a choice made by the spell or ability’s controller and therefore does not count as “choosing” them for those triggers [355.10.d].

Read the exact Watcher ability text and determine whether it uses explicit choice language (for example, 'choose an enemy unit', 'choose up to two enemy units', or 'choose any number of enemy units') or programmatic wording (for example, 'deal 1 to all enemy units' or 'each enemy unit gets -1'). If the ability uses explicit choice language, treat those chosen units as targets/choices. That means the units were 'chosen' by the enemy spell/ability and will satisfy triggers that look for being chosen/targeted by an opponent [355.7] [355.9]. If the ability uses programmatic selection ('all' or 'each' or otherwise determined by characteristics), it is not a choice by the effect’s controller and thus does not 'choose' the units for the purposes of 'when chosen' triggers [355.10.d]. If the ability grants the controller a separate Game Action that lets them choose objects (e.g., 'you may perform X on up to N units'), then those choices are considered targeted per rule [355.12] and would count as being chosen. Apply any relevant timing/interactions (moving targets, changes in legality) per the usual targeting rules and the cited FAQs if the ability is targeting in wording.

If the Watcher ability reads 'choose any number of enemy units' it is targeted and counts as choosing even if zero are chosen [355.13]. If the ability reads 'do X to every enemy unit at battlefield(s)', it is programmatic and does not count as choosing any of them [355.10.d]. If the ability creates multiple separate location-based targeting restrictions (like 'up to one unit at each battlefield'), each separate choice is evaluated independently — movement away from the targeted location can cause the unit to no longer meet that location's restriction on resolution, and a targeted spell still 'remembers' its chosen targets so long as they remain board objects (see related clarification) [FAQ:unleashed#22].

The core distinction is whether the ability 'chooses' units (creating choices/targets) or whether it programmatically affects units based on characteristics. The rules say 'When a card Chooses one or more specific Game Objects to affect, it is Targeted' [355.7]. If a unit is chosen as a target it must be a valid target as defined by the targeting rules [355.9], and being chosen/targeted is what typically triggers 'when chosen by enemy spells or abilities' effects. Conversely, the rules provide an explicit exception for programmatic selection: 'It is programmatically selected based on its characteristics rather than chosen by the spell or ability’s controller. e.g., "Kill all units at a battlefield" targets a battlefield, but does not target any units.' [355.10.d]. That exception is the reason that effects phrased as 'all enemy units' or 'each enemy unit' do not create a 'chosen' relationship and therefore do not trigger 'when chosen' abilities. There is one more nuance: if the effect gives a player a Game Action in which they choose objects (for example, 'you may perform this action on up to N objects'), those choices are considered targeted by rule [355.12]. Also, wording with 'any number' or 'up to' is explicitly handled: choosing any number is still a choice and thus targeted behavior when the wording uses 'choose' [355.13]. Finally, if the ability is indeed targeting, remember the interaction with movement and memory: a targeting spell 'remembers' the objects it chose while they remain board objects, and movement off the board severs that relationship per clarifications [FAQ:unleashed#22]. Putting this together: an ability that literally selects or instructs the controller to choose enemy units will count as 'choosing' them for opponent-triggered 'when chosen' effects [355.7] [355.9]; an ability that simply affects enemy units en masse without making those choices will not count as choosing them [355.10.d].