Steer your glowing creature out from your safe glow, loop around open water, then return to your glow to flood it with your color. Drag or use arrow keys or WASD. Do not let anything touch your open trail before you close the loop.

Online: share one reef with other explorers for two minutes. No anglerfish out there, just each other. Cut a rival trail to send them home, and hold the most reef when the tide goes out.