LogFAQs > #973184706

legendarylemur posted...

What on earth... It's a jank loop caused by negating one of the Graydles. Hilariously it resolves mid way through the loop with a very confusing and rare ruling that the card is simply destroyed to prevent the loop. I believe it's because it's like trying to return to the owner but... simultaneously there's an effect trying to take control of it over and over. I'm not entirely sure cuz it only has partial replay.

Graydle Alligator isn't being negated at all. Marincess Crystal Heart is using its effect to make Marincess Aqua Argonaut unaffected by all other card effects except its own, including Alligator. For some reason (maybe there's something else outside the replay that explains this) this leads to the Argonaut being stuck in a loop between "affected by Crystal Heart, therefore unaffected by Alligator and returned to its owner" and "no longer affected by Crystal Heart, therefore now being affected by Alligator again and taken by the opponent again" so it keeps flipping control.

I don't think the card being destroyed to end the loop is a ruling thing either. In the real life game, the turn player would simply not be allowed to make the attack declaration with Crystal Heart in this situation. Instead, it's a failsafe put into Master Duel itself to stop infinite loops like this that the players can't get out of. If a certain action is repeated too many times without input from the player, it'll automatically put a stop to it by destroying the card it deems responsible for the loop. In this case, I assume the offender was deemed to be the effect of Alligator, but then its "When this card leaves the field, destroy the equipped monster." last effect took Argonaut with it.

Either way, it's still a really wild thing to stumble on.