The last shot out of a bottle of liquor that is on the house. The name comes from the thought of there being a spider in the bottom of the bottle.
Some guy: I'll take a shot of whiskey.
Bartender: Looks like you got the spider. This one's on the house.
Bartender: Looks like you got the spider. This one's on the house.
by SleepyP June 05, 2010