Genex Ally Axel [STBL-EN099] Secret Rare Legacy of Darkness Leviathan can't attack unless you

Leviathan can't attack unless you sacrifice two Islands

you can Special Summon 1 Tuner monster from your Graveyard

based on the number of "Crystal Beast" monsters in your Spell & Trap Card Zone

Set: Arena League 2004 Type: Instant Rarity: Rare Cost: {B} Open a sealed Magic booster pack

and enchantment with mana value X or less

Genex Ally Axel [STBL-EN099] Secret Rare Legacy of Darkness Leviathan can't attack unless youSet: Starstrike Blast Card type: Synchro Effect Monster Rarity: Secret Rare Attack: 2600 Defense: 2000 1 "Genex" Tuner + 1 or more non Tuner monsters. Once per turn, you can discard 1 card to select 1 Level 4 or lower Machine Type monster from your Graveyard, and Special Summon it. The ATK of that monster is doubled until the End Phase, but it cannot attack your opponent directly. Remove that monster from play during your End Phase.