Me and the otyugh go back a ways. The very first D&D adventure I ran - the Fast Play Game based on the Dungeons & Dragons movie from 2000 - had an otyugh as its final boss, although my players never got there.
When I was running B/X, I was stunned to realize that there was never an "official" otyugh write-up for non-Advanced D&D (at least not in the core B/X or BECMI books, or the Rules Cyclopedia). To find one, I ended up going through The Basic Fantasy Field Guide, and converting the one there to use the old-fashioned armor class.
Then, when game time came, I realized that I had left it at home. So, I just winged it; I decided that it was THAC0 18, and had six Hit Dice. The players fought it, and won. As far as I know, none of them were ever aware that I was just making it up off the top of my head. Honestly, that's one of my prouder moments as a DM.
Getting back to the monster itself, I like that I could hypothetically stick one in a dungeon as an explanation for the lack of toilets. This is, in fact, what I did for the abandoned manse the party cleared out to use as a home base; the entire house has one chamber pot, but the otyugh in the basement served as more than enough waste disposal.