A massive spider perched upon tall, stilted legs skitters forward, crackling with eldritch energy as the disheveled body of a robed arcanist swings corpse-like from its clenched mandibles.
Speed 40 ft., climb 30 ft.
Str 22, Dex 17, Con 17, Int 14, Wis 15, Cha 14
Chelicerae cannot replenish spell slots naturally and, instead, extract them from the minds of humanoids locked in its mandibles The chelicerae treats the bodies of grappled spellcasters as a spell point reservoir for as long as the grapple is maintained, draining unused spell slots to power the casting of their own spells, 1 point/spell level.
All 0-level spells become at-will abilities. Whenever the chelicerae wishes to cast any one of its spells known, it consumes a number of spell slots from its victim equal to the spell slots necessary to cast the spell (including increased levels for metamagic feats and so on). If the body has insufficient number of spell slots available, the chelicerae cannot cast that spell. However, the arachnid can also draw out spell slots from drained spellcasters or creatures without magic ability.
As a move action, the chelicerae can inflict 1d4 Wisdom damage to any creature grappled in its mandibles, adding 2 spell slots to its spell reservoir for every point of damage inflicted. A victim is reduced to 0 Wisdom in this manner cannot power any more magical abilities, including 0-level spell slots. Unconscious victims held long-term by the chelicerae do not heal ability damage or regain spell slots while this grapple is maintained.
As long as the arachnid has spell slots on which to draw, it casts spells as an 8th-level sorcerer, but does not gain any other class abilities. Spells points in the reservoir given above assume the chelicerae is encountered with an 8th-level wizard (Wis 12, Int 16) paralyzed within its mandibles with no current Wisdom damage.
Environment any forests, underground, or wastes
Fortunately for spellcasters, these massive arachnids are largely confined to the borders of distant forests and wastes although rumors do persist of the creatures being occasionally spotted in dark alleys of some cities, where they are hunted down with impunity. This is not without cause, for few creatures pose such a threat to arcane and divine spellcasters as chelicerae.
Walking on high, stilted legs, these creatures at first seem like gigantic harvestmen. But more often than not, the arachnids are discovered with the grisly bodies of humanoids dangling morbidly by their heads from the chelicerae’s clenched mandibles.
This hunter prefers to stalk isolated victims, incapacitate them with its poisonous bite, then pin them within its jaws. There their helpless body can hang for days on end as the chelicerae pursues obscure and eldritch tasks. At best, these unfortunates wake up weeks later in a stupor with no memory of the events, far from the location of their capture and drained of vitality and spells. At worst, they find themselves immobilized in a thick cocoon in a high treetop until their body and mind recovers enough to be used again, or they are slain and animated as walking dead to protect the chelicerae.
Midgard Bestiary for Pathfinder RPG, (c) 2012 Open Design LLC; Author: Adam Daigle with Chris Harris, Michael Kortes, James MacKenzie, Rob Manning, Ben McFarland, Carlos Ovalle, Jan Rodewald, Adam Roy, Christina Stiles, James Thomas, and Mike Welham.