Take Her to The Moon For me!

Bing Bong:
Bing Bong was Riley's adorable imaginary friend created during her early childhood. However, as Riley grew older, she stopped playing with him, leaving Bing Bong out of a job and a bit lonely. Drifting around Long Term Memory unbeknownst to the other mental denizens, he collected happy memories he liked into a bottomless bag. He greatly missed the times he shared with Riley and was desperate to not be forgotten until one day when he is discovered by the misplaced emotions Joy and Sadness, who were accidentally ejected from Headquarters. Afraid of their sudden appearance, Bing Bong initially tried to run, but when Joy presents herself, he is thrilled to meet her. As the two need to return to Headquarters, Bing Bong, who has been forgotten for a long time, agrees to help them, more so when Joy tells him she will put him back in business when she gets back. He proposes that they take the Train of Thought that will lead them directly to Headquarters, and shows them the way.

About BingBong[disney.wikia.com]
His Death
;( :(