"W is for Witch" is the Halloween episode of the animated series W.I.T.C.H. It first aired October 28, 2006.
Nerissa attempts to steal the power of the Heart of Earth on Halloween, the one night in the year when the Heart of Earth can be taken by force, namely killing the heart's familiar, Napoleon. The Guardians work with Prince Phobos and the newly released Cedric and Miranda.
In the end, Phobos tricks Nerissa and assumes control over her Seal and absorbs her into it, gaining total elemental control. He then betrays W.I.T.C.H. by claiming the power for himself.
- This episode was aired before "T is for Trauma", "U is for Undivided" and "V is for Victory" during the weekend before Halloween.