goon, n.² — Green’s Dictionary of Slang

goon n.²

also goon dust

[its effects may turn the user into a goon n.¹ (1)]

(drugs) phencyclidine.

1979		H. Feldman et al. Angel Dust 124: The large number of street names it has been accorded over the years: [...] goon.
2001		ONDCP Street Terms 10: Goon — PCP; Goon dust — PCP.