He probably didn't mean for this to happen though...

Still a douchy thing to do

Well your boss should ask for an explanation, and then you tell him what happened. If he didn't, he is not worthy of being a 'boss'.

There are plenty of bosses not worthy of the position but that doesn't give them any less power.

And this is where you plan your co-workers "suicide note".

If you were packing your stuff, and your boss didn't notice what you were doing, I'm pretty sure he is blind and didn't notice you were gone. Seek out the rat and make his computer spontaneously combust.

I feel like this is something that would be discussed in person anyways. Then again, I work in a small business where the boss has time to pull me aside and say "sorry but we are laying you off"

I really hope OP posts back after to let us know how things went. I'm dying with suspense here.

Very true, that is all they need to do.

What I really hoped happen is that the coworker faces up to what he/she did, and talked to OP's boss. It may mean they get fired, but it's not okay for their stupid prank to make someone else lose their job. Even considering coworkers I've really disliked in the past, I would never wish them to be fired over a mistake I made. This world can be unfair enough on its own at times.

At my BF's job they are required to lock their computers if they leave their desk, because the information they deal with is private. So if some unlucky newb forgets to lock theirs, they may have 'unintentionally' sent a few emails about how they are going to Justin Beiber concerts, get a few new backgrounds put up.. Or in extreme cases send a resignation email. Thankfully though the boss usually sends an email back, cause she's used to it.

If it's NOT illegal it should be!

100% illegal. You were deceived by someone claiming to have that authority and you responded accordingly. Go get your job back.

Co-worker doesn't necessarily mean friend. I've had a lot of asshole co-workers.

Whatever the relationship was the one who sent the email to op should have told him that day that it was a joke so op would not miss work

Unless the co-worker's job is shittier than op's.

If that's the case, OP can ask for their old job.

He never said he was at work when he checked the E-mail.

Pretty sure it does.

13-"...I was at work when a co-worker thought it would be funny..." Reading. It's good for you.

8- you're kidding, right?

8, It definitely sounds odd, since you'd need to clear up a few things like getting your final paycheck, returning company property, etc etc but to say you deserve to be fired because of some prank? Uh...no.

A dish best served cold!

Revenge is also sweet. Is revenge ice cream? I like ice cream. :D