Actinodendron

Actinodendron is a genus of cnidarians belonging to the family Actinodendridae. Species in this genus—often called “tree anemones”—feature striking tentacles that branch fractally like miniature trees, a structure that enhances their predatory reach. These fascinating anemones inhabit sandy or rubble substrates across the Indo-Pacific, and some species, notably Actinodendron arboreum (the “hell’s fire anemone”), are highly venomous—their stings can inflict severe skin lesions.