Abstract Sadness is a Rare figure part of the Inside Out collection.
Appearance
Abstract Sadness looks like a thin blue form.
Behavior During Gameplay
All car obstacles are in 2D along with abstract sadness, just like Sadness, she is only able to collect blue memories, when she collects them, they will float around her until she places them in a memory sender.
How to Unlock
Play as Abstract Bing Bong and find Sadness, she will turn abstract when you get close to her, and thus unlocking her in this form.