Clarence Aaron Robbins, billed as C.A Robbins and better known as Tod Robbins, was an American author of horror and mystery fiction, particularly novels and short story collections.

Robbins authored two short story collections and several novels. His work often contains bizarre and frightening plots. His novel The Unholy Three (1917) was twice adapted for the screen, a silent version in 1925 and a sound version in 1930; both adaptations starred Lon Chaney. Robbins was also the author of the short story "Spurs", which was used as the basis for Freaks (1932), a film which later developed a cult following. Some of Robbins's work was later reprinted in the "Creeps" series of horror anthologies edited by Charles Birkin.

In the early 30s he moved to French Riviera and refused to leave during the Nazi occupation of France. He spent the war in a concentration camp and died in Saint-Jean-Cap-Ferrat in 1949 due to the consequences.