Charmed - Episode 706 - Once in a Blue Moon

The Elders' suspicion of Leo (Brian Krause) causes them to assign a new Whitelighter (guest-star TJ Thyne) 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 (Holly Marie Combs), Phoebe (Alyssa Milano) and Paige (Rose McGowan) discover that the beasts are actually The Charmed Ones' themselves, transformed by a blue moon. Meanwhile, Agent Brody (guest-star Kerr Smith) learns Paige's secret and informs her of a powerful new threat, and Phoebe and Leslie (guest-star Nick Lachey) discuss their feelings before saying goodbye.

Paige: (to Phoebe) "You get so emotional when you're PMS."
Phoebe: "Yeah, and you get mean."
Paige: "I do not get mean, I'm above it all, nothing happens to me."
(Piper walks in)
Piper: "Alrighty then!"
(Paige orbs out then back in)
Phoebe: "Oh right, nothing happens to you, you're above it all."
Paige: "Fine, I get a little jumpy."
Piper: "And I get a little pissy, so watch it."
Paige and Phoebe: "We know."

Paige: "We're demons?"
Piper: "No Paige, we are not demons."
Phoebe: "We're monsters."
Paige: "Ok, I knew we were a little testy this time of the month, but this is just crazy!"

Phoebe: "Oh that was just the blue moon. It won't happen for another 50 years."
Piper: "Yeah, and by that time we'll just be a menace to our rest home. So I think you're safe."