Crystalline Nautilus (Foil) 2U
Enchantment Creature — Nautilus
Bestow 3UU (If you cast this card for its bestow cost, it s an Aura spell with enchant creature. It becomes a creature again if it s not attached to a creature.)

When this permanent becomes the target of a spell or ability, sacrifice it.

Enchanted creature gets +4/+4 and has "When this creature becomes the target of a spell or ability, sacrifice it."