Man leaning on mans back to sign contract and stabbs the contract to his back with the fountain pen

Can you offer more information than that?

Like the ending of the goonies? Or did it hurt him?

It could only be... The Running Man (1987)

(The agents is continuing to fill Ben in on his rights.)
Agent:... for cassettes, video tapes, bubble-chip, or all other methods of recording known or unknown. Sign here. Here, here. Here use my back victim.
(Ben signs the contract then stabs the agent in the back with the pen.)
Agent: Aaahh!
Ben: Don't forget to send me a copy.

Classic Arnie!