Track 6 (BTD3)

Track 6 is a track from Bloons Tower Defense 3. It is one of the 8 original tracks in the online version of the game. This track was one of the 4 tracks that were initially locked.

Overview
It seems to be inside a human muscle, with blood flowing around the track.

Trivia

 * It doesn't contain water, but it may contain blood in the middle of the path.