What tool for this screw/nut?

From what I can see from the pic. Not the clearest pic, but a standard hexagonal headed nut ?

Just a conventional socket and ratchet or deep ring spanner.

 

is that actually a nut ?? it does not look like one to me .

 

is the inner a bolt that has sheared off by any chance and the black around is welded on ,having the female thread as its internal diameter ?

 

Or the bolthead is round the other side?

 

Much better photo needed.

 

Decent set of grips. Some pressure on the threaded end to persuade it down/out.

Bit of brute force and a few swear words.

 

it is obviously a screw / bolt thread .if all else fails you drill a hole in it and use a screw extractor .

 

Dunno if it's my eyes or a blurry pic but the head doesn't look exactly hexagonal - has it been previously butchered maybe

If it's the bolt in bottom picture, looks like it's screwed into a plastic moulding so unlikely to be mega tight

Pair of mole grips or similiar might shift it