This is during when Ben and Albedo were fighting over the Polymorphic crystal.. While both of them were beating the shit out of each other, Kai (Ben’s ex-girlfriend and your current girlfriend), Rook, Kevin and Gwen.. Albedo used master command to instantly transform him into Goop them slid off of Ben’s grip then snuck around, took the Polymorphic crystal, inserted it inside his Omnitrix, then it gooed into the Ultimatrix..

Albedo - “HAHAHAHA—“