Protantagonist 

When the protagonist of a movie instead of embracing the role of the heroic figure that struggles to defeat evil, turns to be the antagonist of the story as well.

Ray Kroc is a Protantagonist in Power Hungry.

Protantagonist by RoberFreeloader July 22, 2017

Prantagonist

A character of a story who is the protagonist who, through a series of plot twists, ends up to also be the antagonist

a combination of protagonist and antagonist

Alex Mercer from Prototype could be considered an prantagonist

Prantagonist by AfroNinja117 October 12, 2009

Hentai Protangonistitis 

A certain medical condition where a person has no eyes, but inadvertently gains superpowers: the known side effects are harems, lustful personalities, and Yandere actions: it’s a blessing to most onlookers.

The man across the street has been blessed with Hentai Protangonistitis

Hentai Protangonistitis by Caramel_is_scrumptious October 4, 2019

Prantagonist

When the main characters are both good, but oppose each other.

IN Batman v.s Superman, they were both prantagonists.

Prantagonist by Arkival September 6, 2019