This is a clustering palm with multiple slender gray trunks bristling with fierce black spines from base to crown, giving it a formidable armor-like appearance.  The leaf bases wrap tightly around the stem before dropping away, leaving persistent spine-covered leaf scars.  Its crown is composed of pinnate leaves with deep green leaflets, gracefully arching but guarded by short spines on the petioles.  The inflorescences emerge between the leaves, also spiny, and produce numerous small yellowish to cream flowers.  The fruit is round, ripening to a blackish-purple, and is a favorite of certain birds despite its prickly defenses.  This species’ name horridum is derived from the Latin for “rough” or “bristly,” a perfect nod to its menacing exterior.