Holocron

Mind Prison

Force power · Level 6 · Dark
power-typeForcelevel6alignmentDarkconcentrationtrue

⟜ Requires Mind Trap

Tweaked from 5eYou already know this as 5e Phantasmal Killer — It's your Phantasmal Killer — an illusion only the target sees that traps it in its own terror and deals psychic damage, though here it's an Intelligence save (not Wisdom), it hits even on a save, and the 'prison' flavor replaces the recurring-fear loop.
Failed Int save: deal 5d10 psychic and trap the target in a personal illusion; escape or forced movement deals 10d10 more psychic.
ControlDamage
●●breadth · single target, organic only
TargetingSingle
Use whenyou want to isolate and punish an enemy for any attempt to act
ScalingFlat — no higher-slot scaling.
!A dark-side power — repeated casting carries a corruption cost; concentration up to 1 minute; requires Mind Trap as a prerequisite; no effect on droids or constructs; immune to charmed creatures.
illusionpsychiccontrol-condition
Pairs withMind Trap (prerequisite) · high force save DC builds · party that focuses fire to keep target from breaking out
PlaystyleController

You attempt to bind a creature within an illusory cell that only it perceives. One creature you can see within range must make an Intelligence saving throw. The target succeeds automatically if it is immune to being charmed. On a successful save, the target takes 5d10 psychic damage, and the power ends. On a failed save, the target takes 5d10 psychic damage, and you make the area immediately around the target's space appear dangerous to it in some way. You might cause the target to perceive itself as being surrounded by fire, a storm of blaster-fire, or deadly toxic gas, for example. Whatever form the illusion takes, the target can't see or hear anything beyond it and is restrained for the power's duration. If the target is moved out of the illusion, makes a melee attack through it, or reaches any part of its body through it, the target takes 10d10 psychic damage, and the power ends. This power has no effect on droids or constructs.

Codex
Casting Period
1 action
Range
60 feet
Duration
up to 1 minute
Concentration
Yes