Amorphous: An Oblex can move through a space as narrow as 1 inch without squeezing.
Aversion to Fire: if the Oblex takes fire damage, it has disadvantage on attack rolls and ability checks until the end of its next turn.
Sulfurous Impersonation: as an action, the Oblex can extrude a piece of itself that assumes the appearance of 1 medium or smaller creature whose memories it has stolen. This simulacrum appears, feels, and sounds exactly like the person whose memories it has stolen although it smells faintly of sulfur. The Oblex can impersonate 1d4+ 1 (for player controlled prof mod) different creatures, each one one tethered to its body by a strand of slime that can extend up to 120ft away. For all intents and purposes, the simulacrum is the Oblex meaning the Oblex shares its space simultaneously. The slimy tether is immune to damage but is severed if there is no opening at least 1 inch wide between the oblex's main body and the simulacrum. The simulacrum disappears of the tether is severed.
Psuedopod: Melee weapon attack +7 to hit, reach 5ft 1 target. Hit 1d6 +4 bludgeoning damage and 2d4 psychic damage.
Eat memories: the Oblex targets 1 creature that it can see within 5 ft of it. The target must succeed on a DC 13 wisdom saving throw or take 4d4 psychic damage. And become memory drained until it finishes a short or long rest or it is effected by a restoration spell or heal spell. Constructs, oozes, plants, or undead succeed on the save automatically. This cannot be done to the same creature in the same initiative encounter.