Warp Drifter (CR 4)

Medium Plant (Psionic)
Alignment: Usually neutral
Initiative: +8 (+4 Dex, +4 Improved Initiative); Senses: low-light vision, Listen +9, and Spot +9

AC: 17 (+4 Dex, +3 natural), touch 14, flat-footed 13
Hit Dice: 5d8+10 (32 hp)
Fort +6, Ref +5, Will +2
Speed: Fly 15 ft. (good)
Space: 5 ft./5 ft.
Base Attack +3; Grapple +3
Attack: -
Full Attack: -
Damage: See text
Special Attacks/Actions: Feeding, levitation field, poison spores, psi-like abilities
Abilities: Str 10, Dex 19, Con 15, Int 12, Wis 13, Cha 4
Special Qualities: plant traits, tree shape
Feats: Ability Focus (poison spores); Improved Initiative
Skills: Hide +12, Listen +9, and Spot +9
Advancement: 6-10 HD (Medium); 11-15 HD (Large)
Climate/Terrain: Temperate and cold forest and marsh
Organization: Solitary, pair, or grove (3-5)
Treasure: None

Source: Web

The tattered cap of this giant mushroom swells into shape as it changes from the shape of an ordinary tree. The air ripples around its narrow stalk as it rises slowly into the air.

Warp drifters are fungus tree-mimics that feed on the natural bio-energy of sentient creatures. They often conceal themselves near populated areas and employ their psionic powers to ambush travelers. Their behavior and tactics suggest a considerable intellect, but attempts at communication have proved futile. Warp drifters understand Common and Sylvan, but cannot speak.