Outlast Trials variators are the modifiers that change a trial, from extra traps to stronger enemies. Fandom lists dozens, so this guide groups them by what they change and says which events add their own.
Outlast Trials difficulty levels
Trials run at one of four difficulty levels: Introductory, Psychosurgery, Ultra and Ultra II. Higher levels add variators, and some events lock in their own set at every level; the Chemical Leak guide shows one example.
Outlast Trials variators that change traps
These add or change traps: extra sound traps, extra psychosis mines, proximity mines, explosive, frost and fire traps, hazard vents, deadly traps, sharp glass, surveillance cameras, nausea traps and flame throwers, among others. The Kress Twins bring their own nausea traps. The Door Trap Breaker amp shatters or disarms door traps.
Outlast Trials variators that change enemies
These change who hunts you: stronger enemies, low and high enemy density, increased threat, a deadly Prime Asset, more Pushers, Imposters or Pitchers, an always-present Jaeger, enraged enemies, and special appearances by Leland Coyle, Mother Gooseberry, Franco Barbi, the Kress Twins and Liliya Bogomolova. Read the Ex-Pop page to see which enemies you will meet.
How difficulty and variators combine
From Trial 11 in Escalation Therapy the difficulty is Psychosurgery and an Ultra variator is always present. After Trial 21 it becomes Ultra II, and the second slot is filled by Dual Objectives instead of a random variator. According to the game files, certain variators also carry a point value that the game checks against a maximum and a minimum for the trial number, so the random picks stay inside a range for each trial. See the Escalation guide for the full run.
Variators and amps
Some variators switch an amp off. Fandom notes that the Bad Trip and Hallucinations variators stop the sanity effect of Antitoxin from applying. Check the amp's page before you pick a set for a variator-heavy trial.
Outlast Trials variators FAQ
What are variators in The Outlast Trials?
Modifiers that change a trial's traps, enemies and rules. Higher difficulty levels add more of them.
Do events add variators?
Yes. Chemical Leak ran with the Chemical Leak and Shut Off the Valves variators, and Program Geister uses Enraged Enemies and more Skinner Man scares.