Charmed (1998): Season 7, Episode 20

7 - 20: Imaginary Fiends

Unbeknownst to the sisters, baby Wyatt's new "imaginary" friend is actually a demon named Vicus who is trying to win Wyatt's trust to turn him evil. Meanwhile, Piper casts a spell to be able to understand baby Wyatt, but inadvertently brings 25-year-old Wyatt back from the future.