The name of a mythical super-collector, who
always gets to flea markets/thrift stores/yard sales/boot sales/etc. and purchases all of the worthwhile merchandise you are personally seeking out. Also spelled as "Sum
Guy."
Started in rec.games.video.classic, as the name of an individual
always invoked by sellers who would tell inquiring collectors "yeah, we had a lot of <insert collectible here> until some
guy came in and bought them all." That line, or variations, was so common, that it was determined that there was a single
person wreaking all of this havok, and the sellers were actually stating his name- Sumguy.
Applicable to all frustrated collectors who shop in vain for their favored items.
I found a Vectrex overlay at this yard sale; I asked the
guy running it if he had the Vectrex still, and he said that he had the system, a few dozen games, the 3D Imager, and
light pen, but that Sumguy had just bought it all less than 5 minutes before I got there!
