Bing Bong (Richard Kind)’s Timeline and Summary

Bing Bong meets Joy and Sadness in Long-Term Memory. They're trying to get back to headquarters to restore Riley's Core Memories; Bing Bong offers to help.
On their way to catch the Train of Thought, Bing Bong takes them on a shortcut through Imagination Land that includes a trip through Abstract Thought. (No pun intended.)
Bing Bong takes them on another shortcut. This time they do catch the train, only to have it come screeching to a halt when Riley falls asleep.
Joy and Sadness interrupt one of Riley's dreams, trying to scare her awake and restart the train; as a result, Bing Bong gets apprehended by security and locked up.
Joy and Sadness free Bing Bong. They scare Riley awake and get back on the train.
The train's derailed. As Long-Term Memory crumbles beneath them, Bing Bong and Joy tumble into the Memory Dump.
Bing Bong recovers his rocket ship, and he and Joy try, and fail, to use it to escape the dump multiple times.
On their final attempt, Bing Bong bails at the last minute, allowing Joy to sail to safety without him.
Bing Bong asks Joy to take Riley to the moon for him and fades away into nothingness.