parting gift

Short definition from Wiktionary

Noun

1. 1
   A gift given to someone who is leaving; a leaving present.
2. 2
   An offering given, usually as a consolation prize, to a person who is not the ultimate winner of a contest. Often used in a game show for contestants who are not the grand prize winner.
3. 3
   A final attack or insult by a departing enemy.