Horror Mario

Horror Mario appears similar to his standard counterpart, but with darker colors. He has blood leaking down his eyes and mouth, the former of which is an empty void with small red pupils, and the latter being fanged. He wields a sharp cleaver knife in his blood-stained hand, and is also taller and paler than normal. His face contorts during his poses and when he laughs. Almost halfway through It's-A-Me, Horror Mario goes crazy, his face starts to melt, and his eyes turn completely black.

In Starman Slaughter, Horror Mario resumes his standard appearance (while snapping) until Yoshi.EXE makes him fall off the platform he's standing on by ground pounding on the background POW Block. After returning, he is shown with a melted body, damaged clothes, his right arm missing, and an expression of anger. During the cutscene after Starman Slaughter, Horror Mario regenerates and returns to normal.

In All-Stars, Horror Mario turns into Ultra M and takes on a more tetric and deformed aspect of original Mario. He now has a very tall and almost skeletal body, four arms (where his gloves are now fused with his hands), black shoes with red details, and dark tentacles protruding from behind his body. Ultra M's eyes are not on his face; instead, they're on his hat, similar to Cappy (as seen in the beginning sequence of All-Stars, where his eyes are visible on most characters seen in the mod). In the third and fourth acts of All-Stars, Ultra M is gigantic in size.