The king of Yavimaya's waters pays constant attention to his subjects . . . and thrives on their adulation.

Emperor Crocodile

When you control no other creatures, sacrifice this creature.

Eternal Masters

When you control no other creatures, sacrifice Emperor Crocodile.

Ninth Edition

Eighth Edition

Emperor Crocodile’s ability will trigger if you don’t control another creature, even if it’s only for a brief moment during the resolution of another spell or ability (such as that of Brago, King Eternal).

The ability only checks if you control no other creatures at the time it triggers. It does not check again on resolution, so gaining control of a creature before then will not save Emperor Crocodile.