Ninja Gift 

Ninja Gift - To give someone a gift who is not expecting the gift. This differs from a normal gift because often the event is past and the person cannot give a gift in return, yet feels the obligation to give a gift.

"Bob Ninja Gifted me for Christmas and now I look like the ass because I didn't give him anything!"

Ninja Gift by MysteriousJ December 20, 2008

Ninja gift 

The gift you never saw coming.

Gift recipient: "Omg I can't believe I got a Snuggie from the person who sent me the 'WTF Blanket' video!"
Gift giver: "Ninja gift! Oooaaah!!"

Ninja gift by RealNaughtyRN January 19, 2011

Ninja Gifting 

The Art of gifting an item to a friend or relative, by sneaking into their house and placing said item unwrapped among their personal belongings, in such a way they have no clue who gifted the item to them or where it came from. also can be referred to as Ghost Gifting.

I found a Venus statue in my room, I believe someone has been ninja gifting me while i was at work.

Ninja Gifting by Monroe space kraken-slayer January 30, 2012