Phanquid is an enemy from Final Fantasy Mystic Quest.
It can be killed easily with the Fire spell.
The Phanquid has three phases, depending on how much HP it has left. It initially appears with eight tentacles, two of which are barbed at the end and poised to attack. When a third of its HP is gone, the two tentacles are gone, and the eyes are widened and become more reptilian. The last phase has its "head" lopped over its face.
In the Japanese release, the enemy is referred to as "Pterygotus". Pterygotus is a genus of marine arthropod within the extinct order eurypterida (or Sea Scorpion), and includes some of the largest species of this group.
Its English name is most likely a portmanteau of "phantom" and "squid."