Has Nature, then, her undertaker? Certainly she has. He is appropriately known as the Necrophorus mortuorum, or more popularly as the sexton beetle, for he is equipped with spade and all that is necessary for “undertaking.”
There is much that the human variety might learn from this humble and industrious insect. Whilst he is dressed in a conventional garb of black, he seeks to enliven matters by means of two broad bands of yellow on his back. He is cheery, and when his duties are over for the day he indulges in a little music, not perhaps entirely a matter of art for art’s sake, but like most joyous notes of nature, his immediate object is to attract the attention of the opposite sex.
–Bertram S. Puckle, Funeral customs
Nicrophorus, a genus of beetles including species known as the “carrion beetle,” “burying beetle” and the “sexton beetle,” are nature’s undertakers. They bury the bodies of small vertebrates to create a nest for their larva. Nicrophorus giganticus, as the sages call them, are a gigantic variant capable of burying large mammals, including humanoids and (of course) adventurers.
Whereas their tiny cousins use their club-like antennae to sniff out tiny corpses, the Giant Sexton Beetle is far less patient and will often help living creatures make the transition to grub food.
The giant sexton beetle can detect the odor of blood from up to two miles away. Hunters and trappers consider them a nuisance, as they steal and bury their quarry, but many a traveler has also reported being set upon by sexton beetles after fighting off bandits or brigands.
Giant Sexton Beetle
AC 3 (17), Move 12″/fly 24″, HD 3, Att. 2 (antennae, d6/d6), Ml. 12.
In areas home to a population of Giant Sexton Beetles, roll a d6 on the first round after blood has been spilled and every other round thereafter. On a 1, d4 Giant Sexton Beetles have been attracted by the smell of blood. After a battle, any corpses will eventually draw d4 Giant Sexton Beetles as well, in d6 turns.
The beetles will gather and surround combatants, perhaps waiting to see if one falls, and will attempt to finish off wounded creatures. They will feed on corpses, and will then mate, lay their eggs inside the corpse, and bury it. Larva hatch 2d4 days later and emerge as d6 small (1HD) beetles one week later.
Being beetles they have no treasure and no lair, but the corpses they’ve buried may have valuable personal effects, and can be found by diligent trackers or dogs. Searches may turn up skeletonized corpses (50%) or fresher corpses still swarming with grubs, which will attack if disturbed. (AC 9 (11), Move 3″, HD 1/2, Att. 1 (d4 bite), Ml. n/a)
There is an amazing gallery of sexton beetles here. Note the photos of mite-infested beetles. They look horrific, and suggest a giant beetle made of a swarm of smaller beetles. (That would be a great monster too!)