I'm thinking that perhaps you heard this spoken aloud, and that perhaps what you heard was really "stacks of." That would usually mean, literally, that something was in stacks. But a common reason for things being in stacks is that there are too many of them to organize carefully. Google Books shows me some examples: "He had stacks of files everywhere and file boxes lining any free space on the edges of the walls." "We had stacks of forage, plenty of hams, bacon, &c., and felt that good times were in store for us." "The 78s were easy to find when I started looking here in the late seventies. There were stacks of them all over the place in the flea markets. There were a couple of little shops in Paris that had stacks of old 78s, from the floor to the ceiling."

A "stag"is a male deer. Do you mean "stages of"? stage = etapa, fase