Mizzix's Mastery [Commander 2015] Thrull Island Fish Jasconius can't attack

Island Fish Jasconius can't attack unless defending player controls an Island

(For example

Set: Alpha Edition Type: Enchantment — Aura Rarity: Common Cost: {U}{U} Enchant creature

Set: Coldsnap Promos Type: Token Legendary Creature — Avatar Rarity: Rare Flying

the betrayer

Mizzix's Mastery [Commander 2015] Thrull Island Fish Jasconius can't attackSet: Commander 2015 Type: Sorcery Rarity: Rare Cost: {3}{R} Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery. Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change its text by replacing all instances of "target" with "each.")