Monster: Spelljacker

Spelljackers grab onto a Magic-User’s spell and take its power to rampage around causing trouble.

The Spelljacker is a creature with two parts: the main bulk of its body drifts along suspended in the weightless Astral Sea with a tenuous connection to the Prime Material Plane. On the Prime Material it looks like a wisp of smoke unless it’s riding a spell. If you can Astrally-project you can see the Silver Cord connecting the two and if you sever the Cord the Spelljacker loses its Prime Material part until it regrows in a year and a day.

The Spelljacker wisps around until it finds itself near Magic-Users. It bides its time, watching the kind of spells that come out. It doesn’t understand human thought or language, and it can’t predict what kind of spell will be cast. After the watching period of 1d4 days, every spell cast by an M-U near the Spelljacker has a 1 in 10 chance to be grabbed.

If the Spelljacker grabs hold of a spell, the spell will fail to materialize. The Spelljacker has hitched a ride across the magical conduit into the M-Us brain and now resides there. The specific spell the M-U was going to cast is still there memorized and the M-U doesn’t feel any different. But the next time the M-U casts that spell the Spelljacker will ride the spell out and take the spell’s shape and powers. The spell doesn’t go off the way the M-U intended.

A Spelljacker riding a spell looks like the spell’s area of effect, even for normally invisible spells. The jacked spell also has a continuous duration instead of whatever the spell normally does. Here are some examples:

Detect Invisibility: The Spelljacker looks like a cone of shimmering light in which anything invisible becomes visible temporarily.

Lightning Bolt: Spelljacker looks like the full length of the LB, and anything it crosses must save or take the damage as if it were struck by a LB (I’d say no more than once per round per target regardless of how many times the Spelljacker passes over you during its movement).

Magic Missile: Spelljacker looks like the individual missiles (however many there would be according to the caster’s level) which can strike as Magic Missiles once each per round, but without dissipating like MM normally do on impact.

Raise Dead: Spelljacker looks like a vaguely humanoid white aura which, if it passes into a recent-enough corpse, will raise it from the dead as the spell, once per round.

Transmute Rock to Mud: Spelljacker is a sparkling mass that, when it intersects with stone, softens it as long as it’s present and re-hardens when it leaves.

As you can see, the Spelljacker’s ability is actually much more powerful than the spell it’s riding because it gets the effect constantly, every round, at full movement.

The Spelljacker is immune to weapons except +2 or greater in any form, and as it lacks a typical physiology it’s immune to disease, poison, petrification, etc. It counts as a “monster” for purposes of charms, holds, etc. It’s also extraplanar, so banishing spells can be helpful in either form. Spelljackers are incorporeal so you can’t grapple it or trap it in a cage.

If the Spelljacker is riding a spell, the spell can be cancelled through:
Counterspelling (a Fireball can be cancelled by an M-U casting Fireball as a counterspell),
Anti-spelling (a Fireball could be cancelled by a water or ice-based spell or other flame extinguishing magic or possibly air-controlling magic of 4th level or higher since Fireball is a 3rd level spell), or
Dispelling (the Spelljacker’s hijacked spell is dispelled at 3 higher than the one who cast it).

Any cancellation results in the Spelljacker shedding its spell. It leaves on a 1 in 6 chance per level of the spell used to cancel it (thus, always if you use a 6th level spell), otherwise it hangs around in the periphery to try to grab onto another spell (1 in 10 chance per spell as usual).

Noticing a latent Spelljacker skulking around is very difficult, equal to noticing a 6th level Invisibility effect. True Seeing or similar 6th or higher detection spells can locate it. If pressed in combat when it isn’t riding a spell it generally flees to harass some other unlucky M-U.

Noticing a Spelljacker inside an M-U’s brain requires x-ray vision or life detection, and it shows up as a spectral worm coiling around in there. It can be exorcised through banishment magic, or dispelling (causing it to flee using the chances given above rather than actually rolling to dispel the creature), or the death of the M-U.

Using whatever rule set you use, a Spelljacker’s stats should be mostly useless since it attacks mainly through its spell. For 1e/2e I’d give it 7 HD, AC 0, MV 12″. On the Astral the Spelljacker is a brainy hulk with inscrutable desires (if desire is a thing it experiences at all) and if attacked there will defend itself with any spells it has hijacked in the past cast at 14th level – roll up 2d20 random ones of spell level 1-6. The Astral body has 14 HD, AC 10, MV 6″ (bigger, squishier, and slower, that is).

The Prime Material wisp carries no treasure, but the Astral form generally contains weird minerals, syrupy biles, and symbiotic organs. Make up a crazy table and let your players dig themselves in.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: