Bloodworm (CR 5)

Huge Vermin
Alignment: Always neutral
Initiative: -1 (Dex)

AC: 16 (-2 size, -1 Dex, +9 natural), touch 7, flat-footed 16
Hit Dice: 6d8 (27 hp)
Fort +5, Ref +1, Will +0
Speed: 1 ft., swim 15 ft.
Space: 10 ft./5 ft.
Base Attack +4; Grapple +7
Attack: Bite +2 melee
Full Attack: Bite +2 melee
Damage: Bite 1d8+3
Special Attacks/Actions: Improved grab, blood drain
Abilities: Str 15, Dex 8, Con 10, Int -, Wis 6, Cha 6
Special Qualities: Exposure, Vermin
Feats: -
Skills: Hide +4 and Move Silently +4
Advancement: 7-8 HD (Huge), 9-10 HD (Gargantuan)
Climate/Terrain: River of Blood (Avernus/Baator)
Organization: Solitary, Pack (3-5), Swarm (6-8)
Treasure: None

Source: Converted

Bloodworms are natives of the River of Blood, feeding on those creatures foolish enough to try and ford the congealing flow. They normally remain dormant, buried in the scabby muck at the bottom of the river until disturbed by a boatman's pole, the trod of someone's foot, or the flailing of some creature attempting to swim in the nauseous liquid.

The average blood worm measures 20 feet long and about a foot wide, with a segmented skin of bright pink like an earthworm's. At one end it has a toothy maw with which it latches onto its victims. Bloodworms cannot remain for long outside their river, and quickly shrivel and dry out, resembling a gnarled tree branch when having died from exposure.