Nasty text message idea?

I want to send this guy who played/used me a nasty anonymous text message. He's now "seeing" this other girl even though he's leaving next week and she's moving away.
What can I send him to get my point across but not let him know its me?

You shouldnt go undercover to be rude to people.
"revenge" isnt always as sweet as you mean it to be,and it most likely wont end how you planned.
What message do you have left to send to him? If he left you,and hes moved on,maybe you should do the same?
If he's already made his decision,whats the use of trying to change it?

you could just say to him what the f*ck do you think youre doin sleepin with mywife or sumit like that

honestly? don't sink to that low of a level...there is a wise saying...

"Where you roll in the mud with the pigs you all get dirty...but the pigs love it."

don't roll in the mud.

Why would you do something so childish? You knew right from the beginning how this guy was. All 10 of your questions explains it. Wasnt it obvious that he never really liked you, and yet you still kept pushing it. Just take this as a lesson, and stay away from guys like him. There were a number of red flags, but you just kept ignoring them all. So you cant blame anyone for your ignorance except yourself.

That's really low - get over it.

its best not to get involved
obviosly you still havent got over what happened and want to seek revenge
but its not worth it
its time to get him and the memories of him out of your life and move on