In Mississippi the important thing is hooch, not bar equipment. — Florence King
Q: Does Equipment fall off if you attach it to a manland and it stops being a creature?
A: Yes. If you have an Equipment or “Enchant/Aura Creature” attached to a create and the creature stops being a creature, then the attached card is buried. This happens during the at the beginning of the end step when when the land stops being a creature and state-based actions checked and resolved. So the Aura (Enchant Creature) or Equipment has to check if it’s target is valid and when it checks, the object it was targeting is no longer a legal target so it is placed in the graveyard (if Aura) or stops being equipped.
MrG
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References:
Comprehensive Rules:
301.5 Some artifacts have the subtype “Equipment.” An Equipment can be attached to a creature. It can’t legally be attached to an object that isn’t a creature.
303.4a An Aura spell requires a target, which is defined by its enchant ability.
303.4c If an Aura is enchanting an illegal object or player as defined by its enchant ability and other applicable effects, the object it was attached to no longer exists, or the player it was attached to has left the game, the Aura is put into its owner’s graveyard. (This is a state-based action. See rule 704.)
514.3a At this point, the game checks to see if any state-based actions would be performed and/or any triggered abilities are waiting to be put onto the stack (including those that trigger “at the beginning of the next cleanup step”). If so, those state-based actions are performed, then those triggered abilities are put on the stack, then the active player gets priority. Players may cast spells and activate abilities. Once the stack is empty and all players pass in succession, another cleanup step begins.
704.3 Whenever a player would get priority (see rule 116, “Timing and Priority”), the game checks for any of the listed conditions for state-based actions, then performs all applicable state-based actions simultaneously as a single event. If any state-based actions are performed as a result of a check, the check is repeated; otherwise all triggered abilities that are waiting to be put on the stack are put on the stack, then the check is repeated. Once no more state-based actions have been performed as the result of a check and no triggered abilities are waiting to be put on the stack, the appropriate player gets priority. This process also occurs during the cleanup step (see rule 514), except that if no state- based actions are performed as the result of the step’s first check and no triggered abilities are waiting to be put on the stack, then no player gets priority and the step ends.
704.5n If an Aura is attached to an illegal object or player, or is not attached to an object or player, that Aura is put into its owner’s graveyard.
704.5p If an Equipment or Fortification is attached to an illegal permanent, it becomes unattached from that permanent. It remains on the battlefield.
Links to other explanations:
[stackexchange]…do-auras-and-equipment-stay-on-cards-if-they-stop-being-creatures
[mtgsalvation]…man-lands