DXM is also used recreationally. When exceeding label-specified maximum dosages, dextromethorphan acts as a dissociative anesthetic. Its mechanism of action is via multiple effects, including actions as a nonselective serotonin reuptake inhibitor and a sigma-1 receptor agonist.
Aroldis Chapman has thrown the fastest pitch ever recorded, but he has challengers for baseball's hottest heater in 2017. Ever since Aroldis Chapman delivered a 105 mph fastball to Tony Gwynn Jr., Chapman's name has been synonymous with velocity.
I think Billy Hamilton of the Reds is generally acclaimed as the fastest man in baseball at the moment. The Marlins' Dee Gordon and the Royals' Jarrod Dyson and Terrance Gore (currently in the minors) are also in the running. Plenty more videos of Hamilton here.