Once in a Blue Moon

"Those funky powers, the sharp fangs, the claws, we're the ones who've been attacking the Whitelighters. Something is transforming us."

- Paige to Leo

Once in a Blue Moon is the 6th episode of the seventh season and 140th overall episode of Charmed.

Summary
The Elders' suspicion of Leo causes them to assign a new Whitelighter to the girls. However, when the new Whitelighter is nearly killed by Beasts, the Elders blame the attack on Leo. Trying to prove Leo's innocence, Piper, Phoebe and Paige discover that the Beasts are actually the Charmed Ones themselves, transformed by the Blue Moon. Kyle tells Paige his story in reference to the New Power. The sisters, seeing the Creature Head themselves, realize that Leo isn't so crazy after all.

Characters
Characters in bold appear for the first time in the series.

Potions

 * Paige made vanquishing potions for whoever or whatever was attacking whitelighters.
 * Piper made potions for Leo if they (as Blue Moon Beasts) would attack him.
 * The Charmed Ones threw dispossession potions to dispossess Leo.

Powers

 * Orbing: Type of Teleportation used by Paige, Leo, Marcus and Odin.
 * Telekinetic Orbing: Used by Paige to orb ice cream to her and to orb away a Crystal. She also orbed a television towards a possessed Leo.
 * Molecular Combustion: Piper accidentally blew up a chandelier, a toaster and a vase. She later used it to blow up the smoke alarm in the kitchen.
 * Hovering: Used by Danny to hover while meditating.
 * Healing: Used by the Elders to heal Danny and Marcus.
 * Illusions: Used by an Unseen Force to make Leo see the Creature Head.
 * Optical Energy Blasts: Used by the Avatars to vanquish the Possessor Demon and his tribe.
 * Shimmering: Type of Teleportation used by a Possessor Demon.
 * Teleportation Manipulation: Used by the Avatars to prevent the Possessor Demon from teleportating.
 * Possession: Used by the Possessor Demon to possess Leo.
 * Electrokinesis: Used by Leo (while being possessed) to attack Piper and the Elders. They also used it to attack him and to attack the Charmed Ones (as Blue Moon Beasts).
 * Remote Orbing: Used by Odin to orb Leo to back to Magic School.
 * Molecular Immobilization: Used by Piper to freeze the Possessor Demon in mid-teleportation.
 * Premonition: Phoebe had a dream about beasts,probably showing her what happens to her during black outs as her powers show her the truth.

Terms

 * Blue Moon - A moon phase that traditionally loosens the bonds of magic, on the three days when the blue moon rises.

Artifacts

 * Crystals - The Charmed Ones wanted to use the Crystals to set a trap for whoever or whatever attacked Whitelighters. Since they turned into the Beasts who attacked them, Marcus trapped them in the cage before he fainted.

Magical Beings

 * Danny - A Whitelighter who was supposed to become the Charmed Ones' new Whitelighter. The Charmed Ones (as the Blue Moon Beasts) attacked him.
 * Marcus - A Whitelighter who was sent down as bait for the Charmed Ones' trap for who or what was attacking Whitelighters. When they turned into the Beasts, they attacked him, but he managed to capture them in the Crystal Cage.
 * Possessor Demon - The Avatars obligated him to possess Leo and to attack the Charmed Ones and the Elders, so Leo would join them.
 * Odin - An Elder who was very suspicious of Leo.
 * Alpha, Beta and Gamma - Avatars. They ordered a Possessor Demon to possess Leo, attack his family, and the Elders so he would join them, and not go back to his family.

Mortals

 * Leslie St. Claire - Phoebe's ghost writer. She finally admitted her feelings for him. He left at the end of the episode.
 * Kyle Brody - A Federal Agent. Paige finds out he isn't a demon and he wants the Charmed Ones' help to find out who really killed his parents.

Notes and Trivia
thumb|300px|right|Once in a Blue Moon WB Trailer


 * In this episode it is revealed that every time there are two Blue Moons in a year, the Charmed Ones transform into werewolf-type beasts.
 * According to the show, two Blue Moons in a year appear every 50 years. In reality, two full moons in the same month is what constitutes a Blue Moon. A Blue Moon occurs every two and a half years.
 * Instead of using makeup effects, computer generated effects were used for the beasts, which cost less money.
 * Joel Swetow previously appeared as Avatar Alpha in the season 5 episodes Sam I Am and Centennial Charmed.
 * Piper previously transformed into a beast under the full moon in the episode The Wendigo.
 * It is quite possible that Piper may be able to channel her powers through her eyes, or mind. In this episode she blew up something without even looking at it, although this might have been the effects of the blue moon and PMS.
 * In this episode, it's hinted that Magic School is located somewhere near the Golden Gate Bridge, as the sisters look through the windows and see it.
 * This is the first time since Oh My Goddess! that Piper actually refers to Leo as her husband, while talking to the Avatars at the end of the episode.
 * It's believed by some fans that Magic School may be floating high in the air. Proof of this:
 * In Once in a Blue Moon when they look out the window, it looks too high up compared to where it would be if the building was on the ground.
 * When Zankou attempts to break into Magic School (few episodes later) Zankou falls down from the sky instead of just teleporting.
 * The ice cream Paige is eating is Ben & Jerry's Phish Food which is known to be Rose McGowan's favorite in real life.
 * This marks the sixth and final appearance of Nick Lachey as Leslie St. Claire.
 * The WB used the promo title Blue Moon.
 * The WB use clips of the big bad wolf from Happily Ever After in their trailer for this episode.

Glitches

 * When Piper is about to explain about Leo, Paige orbs ice cream to the table she starts to take off the lid, but in the next shot she has the lid off and is eating it already. She also asks for three spoons but we only see one (Paige's spoon).
 * When the Charmed Ones transform into the beasts, and the Whitelighter starts to orb, they pull him back down, but when they are in orbs they're suppose to be intangible/phased as proven on several occasions where bullets or arrows go through the orbs but don't seem to hurt the whitelighter at all. However, on other occasions, whitelighters could be pulled back down or otherwise affected while orbing away, as Leo did once in Valhalley of the Dolls, Part 1 unleashing his rage against Chris for sending him to Valhalla.
 * When Phoebe talks to Leslie about him leaving, her arms change between shots from hanging by her sides to her hands clasped together in front of her.

International Titles

 * French: Lune Bleue (Blue Moon)
 * Italian: Notti di luna blu (Blue Moon Nights)
 * Czech: Když vyjde modrý měsíc (When Blue Moon Comes Out)
 * Slovak: Za svitu modrého mesiaca (At the Shine of the Blue Moon)
 * Spanish (Spain and Latin America): Noches de luna azul (Blue Moon Nights)
 * Serbian: Jednom u plavom mesecu (Once in a Blue Moon)

Quotes

 * Phoebe: It wasn't demonic, it was just that time of month. Besides it won't happen for another 50 years!
 * Piper: Yeah. By that time we will be a menace to our rest home!