So what does such a chewed-to-the-bone character bring to the horror movie table?
The Horror It Represents:
As they're one of the premier forces actively fucking up the world, the primal fear of powerful, money-grabbing rich dicks is ever-present. Not a day goes by in which a person whom we'd deem a nigh-unbelievable character if we saw them in a movie because he's just too monstrous attempts to run for president or literally sentences people to death by overpricing their medication overnight. It's an attitude that can easily be seen as evil, yet the Greedy Rich Person archetype tends to get used in literally every single other genre except horror. Sure, horror movies have rich guys, too, but they're usually there to finance or otherwise try to profit from whatever creepy masked alien imbecile is hacking their way through the nation.
But what if we took the leprechaun and made it the corrupt corporate executive monster? The greediness is already there, as is the access to powers that ordinary people cannot touch. After that, it's just a matter of portrayal. Luckily, acting powerhouse and professional intense person Robert Carlyle has been playing almost this exact character in the otherwise-goofy Once Upon A Time for approximately 1,000 years now, and manages to be a consistently creepy fucker despite the general PG-ness of the show. Just stick him in a leprechaun movie with a solid script and let him go full Begbie, and watch as this formerly goofy monster becomes the world's New Favorite Thing.