Marcus Babudius Cosmas was a Roman Army captain during the 1st century BC. He commanded the Roman garrison of a Libyan mine in Creta et Cyrene, overseeing the slave laborers. In 73 BC, he greeted the lanista Lentulus Batiatus when he arrived at the mine to purchase some of the slaves to serve as gladiators; he offered several slaves as gladiators before Batiatus chose Spartacus, whom Cosmas had setnenced to death for his rebellious behavior.