Sealock Monster {3}{U}{U}

Creature — Octopus

Sealock Monster can’t attack unless defending player controls an Island.

{5}{U}{U}: Monstrosity 3. (If this creature isn’t monstrous, put three +1/+1 counters on it and it becomes monstrous.)

When Sealock Monster becomes monstrous, target land becomes an Island in addition to its other types.

5/5

Illustrated by Adam Paquette

en ja ⋮

Prints	USD	EUR	TIX
The List	$0.08	€0.07
Duel Decks: Elspeth vs. Kiora	$0.06	€0.04
Theros	$0.08	€0.07	0.03
View all prints →

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 “{T}: Add {U}.” (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. (2013-09-15)