I'm for once on classic D&D's side here. A little. It's silly to have you constantly probing everything to see if it could kill you but assume death is everywhere, and assume that bone piles represent one of the dozens of skeleton monsters. BUT. but but but but. There should be more to it than GOTCHA! and making you feel like a jackass. And a name that comes from a hopping horse. That doesn't mean I want to get into a full bullcrap knowable ecology and God Forbid gambado society...
They don't eat the dead. They eat what eats the dead. However, what eats the dead is pretty awful and deadly, and they are soft and squishy little things that look like 400 shrimp trying to quickly do a Jerry Orbach impression. To help protect themselves, and lure prey, they cover themselves in heaps of bone and discarded armor, which they affix to their body with an adhesive saliva. They are found wherever big piles of the long-dead are found. The necropolis. The catacombs. The killing fields. The butcher's. They are known also as Skullhermits.
Fully semi-erect and unsheathed, they resemble nothing so much as a naked mole rat composed entirely of star-nosed mole noses. Properly armored, they are protected as chain+shield, with only a few wriggly pink bits peeking through the carcass carapace. They are rarely fully glimpsed in either case.
Like alligators, Skullhermits can attacks swiftly and fiercely for like a minute, and lack the endurance to do much but watch they prey scamper away after fully exerting themselves. They wait until their prey is fumbling through their mounds, trying to pry away their exterior 'shells,' and then they snap.
They are immune to carrion crawler paralysis and most acid damage and disease. Their main method of subduing prey is a single long needle-tooth, which they push into the brain of prey. They then use a powerful four-sphinctered mouth to suck their prey hollow. They can eventually even invert flesh and suck it right off the bones.
They have shitty eyesight, and do not watch and wait. They simply lash out in the direction of vibrations, noise, and shadow. In this way even an illusion can attract the attention of a Skullhermit.
Despite their names, Skullhermits, while rare, are usually found in clusters, since their offspring never want to crawl away far, especially when an available food source is present. They can grow to be mammoth sized but are usually the size of a zaftig man.