It had started with something as simple as no longer remembering the name of some of the people from their cases.
Then, Peter didn't notice, but entire people had disappeared. No, not disappeared. They weren't even gone. They were never there to begin with, and never had been. By the time Peter took notice, when Charlie was gone, and then Olivia, it was too late. He stood in a nearly empty lab, his father babbling a poem, something by Kipling. He quickly pulled out his phone, and dialed the first person from 'off world' he found in his contact list.
It was the last thing he did.
And then, he was gone. Shortly thereafter, so was Peter's entire world. And there was only Nothing left.
[ooc: And there he goes. It was always a privilege to play him with everyone, but it's time for me to let go of him. Per the BDE, people in Fandom will remember him, but his universe is now gone.]