1 Genocide Sans Battle
Yes, including the theme
2 The Amalgamates
Amalgamates are a group of characters in the video game "Undertale." They are created through experiments combining different creatures and objects, resulting in bizarre and unsettling forms. The Amalgamates are a reflection of the game's themes of compassion and the consequences of scientific manipulation. Their presence adds a haunting atmosphere to the game's underground world. Should be on a heavy metal album cover
3 Omega Flowey
Also should be on a heavy metal album cover
Needs to be on a metal album cover
4 Undyne's anime super-form
Still having trouble deciding between this and Sans as to which Genocide boss is better overall
5 Genocide Frisk
Determined to brutally murder everything that moves
Also, HE CANNOT THINK, HE CANNOT SPEAK, HE CANNOT ACT, HE'S STUCK WITH LIFE IN HELL
6 Hotland
Literally (industrial) hell in UT form; NEXT
7 Undyne
Undyne is a main character in Toby Fox's 2015 RPG, Undertale. She is the heroic fishlike captain of the Royal Guard, who takes it upon herself to protect the monsters of the Underground. Her name is derived from the word "Undine", and is a pun on the word "Undying". Her most loved monsters are her mentor, King Asgore, her best friend, Papyrus, and her love interest, Alphys. If you don't believe me, just WAIT until the first Pacifist encounter with her
8 Mettaton
Mettaton is a character in the popular 2015 RPG game, Undertale. He is a robot with a soul built by Dr. Alphys, and is the sole television star of the underground. Mettaton is a popular character in the fanbase. His notable features include his legs, and his catchphrase "OH YESSSS!" Still fights you even after you take all of his limbs off
(Also is incredibly badass, most especially the appearance of his NEO form)
Gets points here for actually being metal.
9 Asgore's giant lightsaber trident
Makes him look pretty intimidating, I must say
10 The song title "Metal Crusher"
Hmm, actual song sounds more like Castlevania than anything else if you ask me