twice so far, both times from beer brewed by Lefty. First in the introduction (Larry) and secondly, after you come back to the Lefty's bathroom after you've visited the second location. (a girl who drank the beer with you is on the toilet) There is no realistic depiction but it is implied and the noises won't make you very happy.
A skeleton in a wall suggests someone got walled in, but you never actually see it happen, it's just implied. (and again, cartoonish and brought humorously)