An aggressive predator that can shift between tangible and intangible states

A Phase Spider is an aggressive predator that can shift quickly from an intangible state to attack opponents. When intangible, the phase spider is invisible, insubstantial, and capable of moving in any direction (even up or down), albeit at half-normal speed. As an intangible creature, it can move through solid objects, including living creatures. It can see and hear on the material plane. Sight and hearing on the material plane are limited to 60 feet. A typical phase spider's body is 8 feet long and weighs about 700 pounds. Once one locates its prey, it shifts to a tangible state to attack, attempting to catch its victim off-guard (+2 to hit). The phase spider automatically retreats back to intangible state at the beginning of the next round, before initiative is rolled.

A phase spider possesses the magical ability to phase in and out of the Ethereal Plane. It seems to appear out of nowhere and quickly vanishes after attacking. Its movement on the Ethereal Plane before coming back to the Material Plane makes it seem like it can teleport.

A phase spider possesses the magical ability to phase in and out of the Ethereal Plane. It seems to appear out of nowhere and quickly vanishes after attacking. Its movement on the Ethereal Plane before coming back to the Material Plane makes it seem like it can teleport.

Phase Spider

Plane-Shifting Arachnid Ambusher

Phase spiders appear out of nowhere to attack, then vanish just as swiftly. These horse-size, magical arachnids are endemic to the Ethereal Plane. From vaporous lairs, they peer through the Border Ethereal into the Material Plane. When they detect prey, phase spiders draw close and then shift or "phase" to the Material Plane to attack. They shift between planes of existence and attack from unexpected directions until they overcome their prey or are forced to retreat.

Phase spiders are more intelligent than mundane spiders, but most are cowards. They usually flee if they're outnumbered by creatures capable of seeing them on the Ethereal Plane or pursuing them there. They make exceptions for ghosts and similar spirits, which phase spiders gain sustenance from and pursue as favored prey.

Some sages say you unknowingly occupy the same ethereally coterminous point as a phase spider an average of four times each year.

A spider able to shift in and out of reality during combat

The phase spider is so named because it is able to shift itself subtly in and out of reality during combat. The creature can stay out of phase, waiting to deliver its poisonous bite (victims save at -2; the creature is very deadly). If struck by a phase door spell, the phase spider must remain in phase for eight rounds. Becoming æthereal through magic or other means puts attackers in phase with the creature and they may strike at it with no disadvantage. The webs of this creature are highly sought after for the construction of bags of holding, etc.