some species of coral reef sea cucumbers defend themselves by expelling sticky "cuvierian tubules" to entangle potential predators. these tubules are attached to the respiratory tree in the gut. when startled, these cucumbers may expel the tubules through a tear in the wall of the cloaca. in effect, this squirts sticky threads all over a predator. replacement tubules grow back in one-and-a-half to five weeks, depending on the species. the release of these tubules can also be accompanied by the discharge of a toxic chemical known as , which has similar properties to soap. this chemical can kill any animal in the vicinity and is one more way in which these sedentary animals can defend themselves. other cucumbers, lacking this device, can split their intestinal wall, and spew out their gut and respiratory tree. they regenerate them later. zoologists who experience this believe it to be an impressive deterrent. "the mess one individual can make must be seen to be believed".p81