Porcupine Cactus (CR 1)

Small Plant
Alignment: Always neutral
Initiative: -5 (Dex); Senses: low-light vision

AC: 14 (+1 size, -2 Dex, +5 natural), touch 9, flat-footed 13
Hit Dice: 2d8+4 (13 hp)
Fort +5, Ref -2, Will -4
Speed: 0 ft.
Space: 5 ft./5 ft.
Base Attack +1; Grapple -4
Attack: -
Full Attack: -
Damage: -
Special Attacks/Actions: Detonate, thorns
Abilities: Str -, Dex 7, Con 15, Int -, Wis 2, Cha 1
Special Qualities: plant traits
Feats: -
Skills: -
Advancement: 3-6 HD (Small)
Climate/Terrain: Warm deserts
Organization: Solitary or patch (4-24)
Treasure: None

Source: Sandstorm

This stubby, barrel-shaped cactus bristles with wickedly long thorns.

Porcupine cacti are so named for their unique method of reproduction. They explode in a burst of pulp, seeds, and thorns at the slightest touch.

These plants form roughly circular patches containing dozens of cacti. During long periods of dry weather, they grow very slowly and conserve the limited moisture in their tissues. When porcupine cacti are not ready to reproduce, they have a somewhat flattened shape and their flesh is quite leathery. However, when a sudden rain comes, they absorb prodigious amounts of water, swelling like rain barrels. Large, showy flowers appear within hours and are quickly fertilized by small desert birds that can maneuver safely among the cactus's numerous thorns. The petals drop after a day, and the fertilized plants begin to swell even more with fast-growing seeds. After about a week, they are ready to scatter their offspring.

A turgid porcupine cactus is extremely sensitive to vibration. If a creature chances to brush against it, a strong wind blows up, or a slight tremor shakes the ground, the plant explodes violently. The spray of thorny matter shreds any creatures unfortunate enough to be nearby. Creatures slain by the exploding cactus then conveniently provide fertilizer for the new patch. In patches, one cactus exploding is sufficient to set off a chain reaction of explosions from other cacti in the patch.

A patch of porcupine cacti consists of up to two dozen plants, 5 to 10 feet apart from one another.