covered in slime

Although snakes look slimy, their skin is actually dry to the touch. 尽管蛇看起来黏糊糊的，但实际上它的皮摸上去却是干的。

If you describe a person or their manner as slimy, you mean that they appear to be friendly but in a way that you find unpleasant.

He was the very worst kind of slimy salesman. 他是那种最令人厌恶的谄媚的推销员。