A mock crown made of thorn branches that Roman soldiers placed on Jesus before the Crucifixion.

1. A starfish (Acanthaster planci) of the Pacific region that is covered with long spines and feeds on coral polyps sometimes causing destruction of coral reefs — called also crown-of-thorns starfish
2. Somewhat climbing bushy spurge of Madagascar having long woody spiny stems with few leaves and flowers with scarlet bracts; SYN. Christ thorn, Christ plant, Euphorbia milii.