Oracle Text

Creature — Serpent

This creature doesn't untap during your untap step. {U}{U}, Sacrifice a creature: Untap this creature. Activate only during your upkeep. This creature can't attack unless defending player controls an Island. {U}{U}: This creature gets -1/-0 until end of turn and deals 1 damage to target attacking creature without flying. When you control no Islands, sacrifice this creature.