Mistakes and a Sweaty Marco

What would've happened if the arm that Marco grabbed ahold of had not been Star, rather, a very irritable demon? What would've happened, say, if Tom didn't regret being bonded to the boy?

(yes, I know there is a whole load of blood moon ball fanfiction, just let me try here)
(disclaimer: I do not own Star vs the forces of evil as much as I wish I did, so credit goes to all the creators and authors! thank you )