Piper knew that Percy could control poison, but she hadn't realized it would be that scary. All Piper could do was use charmspeak.
"Percy stop. We're your friends. You shouldn't be doing that."
Percy froze for a moment, but then Tartarus interfered using his own form of charmspeak.
PERCY. YOU KNOW THAT YOU WANT TO KILL THEM. THEY ALL LEFT YOU EXCEPT ANNABETH, THEN SHE KEPT THE SECRET OF THE CHILD FROM YOU AND THE REASON YOU DIED WAS BECAUSE SHE HAD AFFECTED YOUR VISION.
Percy snarled and swept his sword at Piper. The only thing to deflect the sword was a gust of wind that Jason had sent.
"Percy don't listen to him. He tricked you. We're your friends."
DON'T LISTEN TO THAT WITCH. SHE IS USING MAGIC IN HER VOICE.
It was a back and forth battle between Piper's charmspeak and Tartarus' voice. Until finally Hazel interfered placing Percy in a Mist jail. Percy struck at it and shouted. The rest of them started to surround the cage, but Percy controlled the poison making it surround him like a barrier. There was no chance for them to get him, so they ran.
Annabeth was crying and once they were back outside Hazel released the cage. They found Blackjack outside and then they left to Camp Half Blood along with the pegasus. The whole time Blackjack was whining and whimpering.