pseudopod

noun

1. A temporary projection of the cytoplasm of certain cells, such as phagocytes, or of certain unicellular organisms, such as amoebas, that serves in locomotion.
2. A projection acting as a foot in certain insect larvae.
3. (broadly)An extension or projection from something.

   “A pseudopod of blackness elongated itself from the central mass and like a great tentacle clutched the corpse-like being, dragged it back to the pit and over the brink.”