As with the Phoenix mutant, The Skeleton King's appearance changes noticeably as he evolves. His basic form appears as a simple headstone, orbited by a pair of glowing spheres.
Its bronze variant is relatively the same, however, now takes on a more regal appearance. The headstone has now taken on a more hourglass-like shape, and is adorned by five spikes.
In its silver form, the tombstone has been damaged, and The King's head is now risen from the ground.
From silver and onward, The Skeleton King appears as a sea foam green skeleton, with a beard that fades into his jawline. In his golden form, he now wears spiked, bronze armor over a purple garment, and has a silver-buckled belt wrapped around his waist.
In his platinum form, he now gives off wisps of smoke as he moves, as well as gaining a crown and cloak. The buckle on his belt now also matches the color scheme of his armor.
- Attack: High
- Life: Weak
- Speed: Fast
Darwin had an idea when he started to play with the corpses in the old city graveyard. He wanted to resurrect the king of the forgotten city that was buried here. And so he did. The Skeleton King is now back in the world of the living and ready to haunt your nightmares.
- This mutant's appearance and mutopedia entry might be a reference to Martyr Logarius. A boss from the video game, Bloodborne.
- This mutant also is a nod to old Hero "Skeleton King", who got replaced by Wraith King in the MOBA game DOTA 2.
- Possible reference to Skeleton King from Diablo series.