The flasher scorpionfish was first formally described in 1910 by the Australian ichthyologist James Douglas Ogilby with the type locality given as Bulwer Island near Brisbane.

[3] The flasher scorpionfish has a broad, spiny head with a wide space between the eyes, a highly arched back, and a divided upper opercular spine.

The general color of this fish is brown mottled with white, and it can grow to a length of 13 cm (5 in).

This fish is one of five very similar species of humpback scorpionfish and can be distinguished from S. diabolus, S. gibbosa, and S. obtusa by the markings on the inside of the pectoral fin.

[4] S. macrochir is typically found on soft substrates, where it sometimes buries itself, camouflaged among rubble where it lies in wait for passing prey.