This thing does not drop, I've killed nearly 30 of these and have to keep going back to PoFear. Best concentration of the Amygdalans is in the temple, but good luck getting it to drop.
update: finally got the tendril after killing about half a dozen more or so, was the only one I've seen. Dropped off an Amygdalan knight.
Edited, Apr 30th 2020 2:16am by lemonjello23