Freeza from dragon ball especially with his voice… Akira Toriyama designed him from what he thought monsters looked like in his childhood.
orochimaru from naruto, cause he thrives off of other human’s bodies in hopes of saving his own. His cold white skin and glowing yellow, snake-slit eyes
remind us of what he represents: a snake. We eventually see him go onto transform into a giant snake. Coincidence? I think not.
Prime Minister Kamea (or however you spell it) from Speed Grapher, followed closely behind by that dentist euphoric, then the ballet euphoric (that noodly bendy guy), hell most of the euphorics from that show were creepy.