The Repulsion Gel is a testing element used in the Enrichment Center several decades before Portal, and appears in Portal 2.
All joking aside, that did happen - broke every bone in his legs. All Discussions Screenshots Artwork Broadcasts Videos Workshop News Guides Reviews.

But informative. ―Cave Johnson.
Hahaha.

It is one of three types of Mobility Gels. Tragic. The Propulsion Gel is a testing element used in the Enrichment Center several decades before Portal, and appears in Portal 2. It is one of three types of Mobility Gels. "Last poor son of a gun got blue paint. Portal 2. Or so I'm told." It is one of four types of Mobility Gels. Propulsion Gel, also known as Speed Gel, is a testing element used in the Enrichment Center several decades before Portal and introduced in Portal 2.