Sealock Monster

three generic mana one blue mana Creature — OctopusPower and toughness5/5

This creature can't attack unless defending player controls an Island.

five generic mana one blue mana : Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

When this creature becomes monstrous, target land becomes an Island in addition to its other types.

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0.11 $

Foil 0.41 $

14 printings · up to 0.28 $

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Sealock Monster rulings

2013-09-15
The effect making the land an Island doesn't have a duration and will last indefinitely. The land retains any land types and abilities it already had. An Island has the ability “: Add .”
2013-09-15
Once a creature becomes monstrous, it can't become monstrous again. If the creature is already monstrous when the monstrosity ability resolves, nothing happens.
2013-09-15
Monstrous isn't an ability that a creature has. It's just something true about that creature. If the creature stops being a creature or loses its abilities, it will continue to be monstrous.
2013-09-15
An ability that triggers when a creature becomes monstrous won't trigger if that creature isn't on the battlefield when its monstrosity ability resolves.

Sealock Monster keyword rules

Monstrosity Rule 701.31

“Monstrosity N” means “If this permanent isn’t monstrous, put N +1/+1 counters on it and it becomes monstrous.”

Monstrous is a designation that has no rules meaning other than to act as a marker that the monstrosity action and other spells and abilities can identify. Only permanents can be or become monstrous. Once a permanent becomes monstrous, it stays monstrous until it leaves the battlefield. Monstrous is neither an ability nor part of the permanent’s copiable values.

If a permanent’s ability instructs a player to “monstrosity X,” other abilities of that permanent may also refer to X. The value of X in those abilities is equal to the value of X as that permanent became monstrous.