pink pony e-mail 

An e-mail intended to embarrass the sender, sent without senders knowledge or approval - sometimes referencing how much the sender likes pink ponies.
Usually done when someone leaves a computer unattended and unlocked, enabling anyone to do things on behalf of the logged in user.
Other variations involve changing settings and making minor changes on the computer to could be noticed immediately or much later.

Dane left his computer unlocked so I sent a pink pony e-mail from his account to everyone in his contact list saying he would buy them lunch.

I totally pink ponied Jerehmiah by changing his desktop background.

pink pony e-mail by LowAmmo July 13, 2012