T10.1

A heavy, oily taste fills the air.

Searching the Floor
Perception DC 22: You observe a thin layer of sticky tar on the floor.

May burn the tar off, or make Acrobatics DC 20 to move across without being entangled in the tar, though at half speed.

If missed, target is entangled, and becomes susceptible to catching fire from any source of flame. If lit on fire, the tar burns intensely for 1 round; it deals 2d6 points of fire damage and is destroyed in the process.

From R10
''You leave the larder behind you and crouch through a small opening of a tunnel before you can stand again. As you walk along, you've noted that it's gotten less warm.''

From R18
Ahead of you is a dark tunnel...it has gotten warmer as you've walked along and you have to crouch to get through the opening at the end.