Today’s 1st edition Advanced Dungeons & Dragons Monster Manual Sketch is the reprehensible roper.
The roper is found in subterranean caverns. Looking something like a 9 foot long cigar and able to disguise itself as a stalagmite, a pillar or even a “hump” on the ground, a closer inspection reveals what “appears to be a mass of foul festering corruption.”
However, adventurers foolish enough to carry out such a close inspection are likely to encounter the feature which gives the roper its name: six “strong, sticky rope-like excretion[s],” which shoot out to grab (and poison) its prey. The dazed unfortunate is then dragged into the roper’s “toothy maw” and “quickly devoured.”
The AD&D dungeon is full of these ghastly well-disguised monsters, including the piercer (a stalactite that suddenly drops from the ceiling to pierce, kill and devour passers-by), the water weird (which can hide in pools, fountains or even barrels of wine), the lurker above (which pretends to be the ceiling), the trapper (which pretends to be the floor) and my personal favourite, the mimic (which can pretend to be practically anything, but is particularly fond of mimicking a treasure chest).
My advice? Stay above ground at all times.
This was a commissioned Monster Manual sketch. I’m still taking requests (for a limited time) here.