Xolatoyac, the Smiling Flood

The Lost Caverns of Ixalan Commander · #8 · Mythic

Legendary Creature — Salamander Serpent

Whenever Xolatoyac enters or attacks, put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. At the beginning of your end step, untap each permanent you control with a counter on it.