So in converting some Pathfinder modules over to BECMI, I'll post the monsters that are specific to the module over as well.
So the first set is from the modules, "Tears at Bitter Manor"
Abandoned One
by BouvAC 3
HD 5+15******
MV 90'(30')
#AT 2 or Special
DMG 1d8+3/1d8+3 or Special
THACO 13
SA F5
ML 12
AL C
XP 1275
Special Attack: Curse of Oblivion - Three times per day, an abandoned one can make one creature disappear (Save vs. Breath Weapon) and can last up to 12 hours or until the abandoned one is destroyed. Actions do not make the target appear at all nor can they be heard. They can still attack and cast spells, be smelled, felt, or the sound of their movement.
Forgotten Friend - Anyone impacted by the Curse of Oblivion, their allies must make a save vs. spell or forget the target exists for the duration of the Curse.
Selective Invisibility - The Abandoned One can become invisible to anyone it hasn't attacked.
Abandoned Ones are soldiers who died while en-route to their destination yet didn't receive proper burial or rites and now wish the same upon the living. They are bound to the area in which they died.