Technically  Finn's trident isn't a trident.  It's a glaive, a general catch all category for polearms with blades on the end.  Not saying you shouldn't have it or anything and you are free to call it what you like. I just don't want you getting the wrong idea about real life terms.

Also that last fantasy trident is a very poor design.  Tridents are made to catch on limbs and snag on armour, that way you can pull and push your enemy when they are caught and keep them off balance.

Don't mess with a retiarius!