The man in his 20s was found nailed to a fence, with a nail through each hand, shortly after midnight.
Two vans, one belonging to the injured man, were found on fire in the car park near Dundarave Park.
Police said paramilitary involvement was one key line of inquiry.
Graffiti on nearby public toilets has been linked to the assault and arson.
The Police Service of Northern Ireland (PSNI) said the man was left with potentially life-changing but not life-threatening injuries.
Police said it was a “sinister attack.”
This was almost certainly a “punishment” carried out by loyalist paramilitaries against someone they didn’t like, possibly for being a tout. I haven’t been back for a few years, but Bushmills is kind of a sad place. Aside from the distillery it’s mostly boarded up shopfronts painted to look like they’re still occupied.
Those still happen? I honestly believed these things were firmly in the past.