1 definition by Bryan John
A condition in which a Costco shopper on a random shopping trip will purchase bulk items not needed but are blinded by the deal despite the large quantity that will not be used.
Witness: "That guy must be suffering from Costcosis. His cart has a 3-pack of 20lb tubs of mayo."
Person suffering from Costcosis: "That's a good price for a 3-pack of 20lb tubs of mayo."
Person suffering from Costcosis: "That's a good price for a 3-pack of 20lb tubs of mayo."
by Bryan John February 2, 2011