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.
Near Mint - $0.10
Lightly Played - $0.10
Played - $0.10
Heavily Played - $0.10
Damaged - $0.10
Near Mint Non-English - $0.10
Lightly Played Non-English - $0.10
Played Non-English - $0.10
Heavily Played Non-English - $0.10
Damaged Non-English - $0.10