Tumbling Mound (CR 3)

Medium Plant
Alignment: Always Neutral
Initiative: +1 (Dex); Senses: darkvision 60 ft., low-light vision, and Spot +3

AC: 17 (+1 Dex, +6 natural), touch 11, flat-footed 16
Hit Dice: 6d8+12 (39 hp)
Fort +7, Ref +3, Will +2
Speed: 30 ft.
Space: 5 ft./5 ft.
Base Attack +4; Grapple +7
Attack: Slam +7 melee
Full Attack: 2 slams +7 melee
Damage: Slam 2d6+3
Special Attacks/Actions: Blood drain, improved grab, thorns 2d4
Abilities: Str 16, Dex 12, Con 15, Int 5, Wis 11, Cha 6
Special Qualities: plant traits, resistance to fire 10
Feats: Improved Overrun; Power Attack; Track
Skills: Climb +6, Hide +1*, Spot +3, and Survival +3
Advancement: 7-10 HD (Medium); 11-18 HD (Large)
Climate/Terrain: Warm deserts
Organization: Solitary or cluster (5-8)
Treasure: 1/10th coins, 50% goods, 50% items

Source: Sandstorm

This mass of twisted brush looks like a particularly large tumbleweed covered with sharp thorns.

A tumbling mound appears to be a roughly spherical mass of dried brush. In truth, it is actually an intelligent, carnivorous plant that imitates the form of harmless dead vegetation. Its brain and major sensory organs are located in a lump in the center of its body.

Tumbling mounds move about virtually silently, and often go unnoticed due to their similarity to tumbleweeds. They often lurk in clumps of vegetation, then tumble out to attack when their prey is sleeping or otherwise off guard. Travelers tell stories of waking up to find tumbling mounds feeding off their companions, and of taking flight, pursued by seemingly tireless clusters of the thorny monsters.