River Bed

 is an Advanced Difficulty track in Bloons Tower Defense 4.

Overview
It looks like a dried up river with some rocks on it. There is some grass and stone near it.

Trivia

 * The track appears to be in the shape of an Omega symbol.
 * Since bloons can move side by side, sometimes more than one bloon will enter at a time.
 * The MochiCoins description of this track calls it simply "Stream Track". The track is wide, allowing multiple bloons to move side by side along the track.