Sealock Monster (DDO-042) - Duel Decks: Elspeth vs. Kiora

This creature can't attack unless defending player controls an Island.
{5}: 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.