Dweomer Day: Phase Trap

n.b. Dweomer Day is a series in which I convert a spell from an earlier edition of D&D to 5E or update a homebrew spell from previous editions/campaigns.

Do you like a niche spell? I love a niche spell. The kind of spell that a D&D player might ask, “why would I ever bother to prepare this spell unless I happened to know I was going to be in that exact circumstance or face that specific kind of foe?”

My answer to that question is, “You probably wouldn’t, but trying to foresee events and plan for eventualities is part of the fun of the game. . . at least for me.”

And anyway, imagine the satisfaction you’d have if, when attacked by a ghost taking corporeal form, you could force it back to the ethereal form where it cannot strangle the heir to Corpus Manor or whatever the plot of your adventure might be. I imagine this kind of spell having being researched by a wizard seeking to do battle with his orcish sorcerer rival and his kennel full of blinking hellhounds.

My point is that not every spell needs to be generally useful, though I do think 5E spell moved in that direction, making spells a lot more powerful in some ways (though the limitation of concentration in 5E is my favorite thing about this edition second only to short rests and hit dice).

This spell – called “Phase Trap” – first appeared in Dragon Magazine #92‘s “Pages from the Mages” by Ed Greenwood, one of several spells found in a magical spell book called “Aubayreer’s Workbook.”

“Aubayreer’s Workbook” is “fashioned of a long strip of green hiexel bark, folded and refolded upon itself accordion-fashion. It is bound, protected, between two rectangular pieces of oiled wood held together with hempen cord. Upon one of the boards is carved a rune.” According to Greenwood, the book was the work of a wizard from the Dalelands who founded a “sorcerous dynasty” in Algarond.

I have included the full text of the original 1E version below.

My version is much more succinct and does not include references to edge cases. I likes spell explanations/descriptions to be as brief and clear as possible and allowing the DM to make his own ruling on possible edge cases. Based on how a xorn’s “Earth Glide” power is described now, for example, it felt pointless to reference it because it would not fall under the purview of “phasing” (despite a xorn just being an ugly alien big-mouthed four-armed version of Kitty Pryde). I did decide that shoving a creature back into another planar phase and trapping it there against its will should do some psychic damage, taking less if they resist the effect due to the strain of it. I also decided to make it a reaction spell, so it could be cast dramatically and if it succeeds can change the whole tenor of a combat early on.

The biggest change is that I decided it could effect someone using the Plane Shift spell (though only if specifically used to enter the ethereal or astral); a spell the original explicitly explains cannot be effected by Phase Trap. Furthermore, I included rules for what happens is someone else targets the affected creature with a spell meant to shift their phase while under the effect of phase trap. These rules are also modified by whether the spell is upcast, which does additional damage based on the level spell slot used to cast the spell.

As for the material component, since I dropped the spell level by one between versions, I decided to balance out the spell with a consumed component. I like giving player characters something to spend money on.

Anyway, how you adapt this spell? Would you even bother? Is there some other way it should work in your eyes or something else it should do?