tomato can

Etymology
Presumably because of tendency to bleed when battered, tomato juice leaking from a can being a metaphor for bleeding.

Noun

 * 1)  An inferior fighter in the sport of boxing. The insinuation is that an up-and-coming fighter takes on a "tomato can" to burnish his reputation and record.
 * 2)  By extension, an opponent who presents little challenge.
 * 3)  A boxer who takes a dive, or loses a fight on purpose.