Krark's Thumb

[Redrighthand]

Hypothetically, if one were to have a {mirror gallery} in play to allow for two {Krark's Thumb} would this create an endless coin flipping loop thus ending in a draw as the game can't move forward?

[DrainCleaner]

My brain hurts

[Nymuera]

This is a good one

[Nymuera]

Relevant rule #1
104.4b: If a game that's not using the limited range of influence option (including a two-player game) somehow enters a "loop" of mandatory actions, repeating a sequence of events with no way to stop, the game is a draw. Loops that contain an optional action don't result in a draw.

[Gorzo]

Sadly, no, no loop is created. The thumb is a replacement effect, not a triggered ability, so it doesn't cause trigger-bouncing.  Here's a quote from a judge on gatherer, talking about this exact interaction:

"Replacement effects do not trigger, they just replace the specified event with something else. And a single replacement effect can only be applied to a single event once. So this does not create a loop. What happens with two Thumbs in play is that when you would flip one coin, you flip four and choose one."

[Nymuera]

More relevant rule #2

614.5.: A replacement effect doesn't invoke itself repeatedly; it gets only one opportunity to affect an event or any modified events that may replace it.
Example: A player controls two permanents, each with an ability that reads "If a creature you control would deal damage to a creature or player, it deals double that damage to that creature or player instead." A creature that normally deals 2 damage will deal 8 damage -- not just 4, and not an infinite amount.

[Redrighthand]

Hey everybody, thanks for the great answers, I really appreciate the discussion too!!

Great job!