tarpit

or tar pit

[tahr-pit]
noun
  1. seepage of natural tar or asphalt, especially an accumulation that has acted as a natural trap into which animals have fallen and sunk and had their bones preserved.

Origin of tarpit

First recorded in 1830–40; tar1 + pit1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018