Scarlet Witch: Winds of Destiny, from above and below, change!
In the comics, Nicholas Scratch was the leader of Salem's Seven made up of Brutacus the Lion-Man, Gazelle, Hydron, Reptilla the Snake-Woman, Thornn, Vakume, and Vertigo (not the Vertigo from X-Men who messes with people's heads).
The Grim Reaper is actually Simon Williams/Wonder Man's brother Eric Williams. Armed with an electro-magnetic current-emitting scythe designed by the Tinkerer, he became the Grim Reaper to avenge his brother's death (like in this show and comics).
Obscure 1970's villain group The Salem Seven appear in this episode, and are actually kind of cool here.
Agatha Harkness taught the Scarlet Witch in the comics. She also appeared in one episode of "X-Men: Evolution" (episode #28: "The HeX Factor").
A villain named the Grim Reaper (who is actually Wonder Man's brother) has a cameo role here.
Agatha's familiar cat is named Ebony.
Nicholas Scratch mentions that the Scarlet Witch is a mutant.
This is the return of Wonder Man and the only appearance of Agatha Harkness and the rest of the people in New Salem.
The episode title is named after the fictional fairy tale story, The Sorcerer's Apprentice.