Properties:
Cannot jump when touching it
Slippery (Ice-like properties)
Blue Text
I found some blue text in the game. Follow the blue text, it reveals something.
A theory, there must be one in every bonus stage. There are confirmed ones being in Rotten Orchard, Civilised Abscess, and Divine Paradox. We just need to find some in Grease Puppet and Ruptured Organ to confirm this theory.
Outcome of following the blue text (Rotten Orchard)
Around in the bonus levels there are symbols scattered around. I haven't decoded them yet.
(Note: Some may be flipped or backwards by accident)