Displacer Beast: Displacer Beasts (which first appeared in Supplement I) look like pumas with dirty big spiked tentacles on their shoulders, and they also appear 3 feet away from their actual locations due to their ‘molecular vibrations’. They haven’t changed at all from Supplement I, although the description no longer notes that they have six legs (though the illustrations shows them this way). It’s interesting that a pack is always made…

Continued here:
AD&D Monster Manual part 10