Thousand Tails Watcher effect ruin runner?

The Thousand-Tailed Watcher has the following ability:

"When you play me, give enemy units -3 might this turn, to a minimum of 1 might."

Here are some important details regarding how this effect functions:

• It does not target: The ability does not "choose" specific units; it programmatically selects all enemy units currently on the board at the time of resolution. Because it does not target, it cannot be countered by cards like Not So Fast that require a targeted ability (RiftJudge FAQ #9386, #7280).
• "Snapshot" effect: The ability "snapshots" the battlefield at the moment it resolves. It only applies the -3 Might reduction to enemy units present at that specific time. Units that enter play after the ability has fully resolved are not affected (RiftJudge FAQ #10209, #9586).
• Chain Interaction: Because it is a "When you play me" triggered ability, it uses the chain. You and your opponent may play [Reaction] speed cards in response to the trigger before it resolves. If a unit is played as a reaction to this trigger, that unit will be on the board when the trigger resolves and will be affected by the debuff (RiftJudge FAQ #10506, #10209).
• Minimum Might: The reduction cannot bring a unit's Might below 1 (RiftJudge FAQ #8680).

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