Deathweed (CR 4)

Medium Plant (Aquatic)
Alignment: Neutral
Initiative: +0; Senses: underwater sense

AC: 13 (+3 natural), touch 10, flat-footed 13
Hit Dice: 6d8+12 (39 hp)
Fort +7, Ref +2, Will +1
Speed: Swim 10 ft. (see text)
Space: 5 ft./5 ft.
Base Attack +4; Grapple +0
Attack: Grab +9 melee
Full Attack: Grab +9 melee
Damage: Grab 0
Special Attacks/Actions: Constrict 2d6+7, drain energy, improved grab, psionics
Abilities: Str 20, Dex 11, Con 15, Int 4, Wis 9, Cha 14
Special Qualities: Brood colony, plant traits
Feats: --
Skills: Hide +5*
Advancement: 7-12 HD (Medium); 13-18 HD (Large)
Climate/Terrain: Any aquatic
Organization: Solitary, pair, or brood (3-12) [or pack 3-12 see text]
Treasure: Half standard (inorganic only)

Source: Web

Deathweed is a deadly psionic plant that preys on ocean creatures and feeds on their psionic energies.

This dark green cluster of seaweed possesses strands 5 to 6 feet long, and it is adept at blending in with its surroundings. Tiny fish often take shelter from predators among its stalks.

Aquatic Subtype

Creatures with the aquatic subtype always have swim speeds and thus can move in water without making Swim checks. An aquatic creature can breathe underwater. It cannot also breathe air unless it has the amphibious special quality.