Pylorobranchus hearstorum, the gigantic worm eel, is a species of marine ray-finned fish belonging to the subfamily Myrophinae, the worm eels, in the family Ophichthidae, which also includes the snake eels.

This species is known from a single specimen, the holotype collected from the Verde Island Passage in the Philippines at 13.583-13.575°N, 120.382-120.411°E from a depth between 892 and 966 m (2,927 and 3,169 ft).

The species was described in 2014 by the American marine biologist John E.

[2] The specific name honours the friends of McCosker and philanthropists William and Margaret Hearst, who sponsored the expedition the holotype was collected on.

[3] This single known specimen of this species had a total length of 121.8 cm (48.0 in).