Adjective
Gigeresque (comparative more Gigeresque, superlative most Gigeresque)
Reminiscent of H. R. Giger (born 1940), Swiss surrealist painter best known for nightmarish biomechanical imagery.
The Witch Queen (Julie Engelbrecht) has a Gigeresque ponytail of spinal-column bones and lives in a tree that pulses with malevolent life. Source: Internet