What would cause oil to puke out of this hose?

 

Overfilling your transmission.
That is your transmission breather hose.

 

Or the primary is overfilled. That hose also vents the primary through the hollow transmission mainshaft.

 

Or a leak between the primary and the transmission if the primary is overfilled?

 

Or a friend who is messing with you

 

Some of my riding buddies pulled that stunt in me when I first got my bike (24 years ago). While I was at breakfast, a large oil slick mysteriously appeared under my bike.

 

Think the indi over filled it then since he had the side cover plate off and said oh I used the wrong size bottle and opened the drain twice to let some out. Guess he didn't let enough out. It was alight brownish color.