Picture of Firefox Pranks!
Using add-ons in Firefox to enhance your experience is boring. For April Fools' Day, lets make the experience a little more bizarre.

Since these add-ons were meant to be installed on a victim's computer you'll only need two things:

- a victim who uses Firefox as his or her regular browser
- access to the victim's computer

To keep it simple, here are the links to all of the add-ons for your one-stop shopping pleasure. Each step will explain what each of these does. Just click on a link to install it in Firefox.

- Two Steps Back
- Rick Rollr
(Video removed by YouTube)
- The Devil's Inbox
- Highs and Lows
- Sarcasm Enhancer
- What Did You Say?
- For real
- Watch it
- Dsmvwlr
- Total Confusion Combo Pack!
(Updated 3/30)
- Total Confusion Combo Pack! (non April Fools' Day version)

If you want to hit your victim with everything, you can go for the Total Confusion Combo Pack. The combo pack is set to only work on April 1st, so you can install it now, and nothing will happen until then. Also, throughout the day, the pranks become more and more frequent!

 All of these can be removed simply by going to Tools > Add-ons and uninstalling them.

Scripting by zachninme. Without whom this would not have happened.

These add-ons started out as Greasemonkey scripts and were converted to add-ons with this script compiler.

All code linked to, and mentioned in this Instructable is licensed under the GPL.

UPDATE (3/31/2010): I made these scripts a while ago and haven't tested them since then. Since youtube removed the rickroll video it does not work any more. You are more than welcome to substitute a new video in that script or change any of these for that matter.

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Step 1: Two Steps Back

Picture of Two Steps Back
Once in a while the browser will go two links back instead of the next link forward. This is pretty subtle and will definitely frustrate someone and make them think they're going crazy. We recommend that you let them in on the joke before too long.

Source Code

Step 2: Rick Rollr

Picture of Rick Rollr
Getting people to click on links that sends them to the Rick Roll video is hard. They're on to your silly ways, but what if there was a 2% chance that any link, on any page, would Rick Roll them? Yeah, it would drive 'em nuts.

if(Math.random() > 0.98){
   window.location.href = "http://www.google.com";

That's a 2% chance of your window being sent to the google page. Tweak the number between 0 and 1 for odds of it happening and the URL for the target video.

Step 3: The Devil's Inbox

Picture of The Devil's Inbox
If your victim uses Gmail, then get ready to send their Inbox to hell. There's a good chance that their Inbox count will be stuck at 666. The odds of this happening? 66.6%

Source code

Step 4: Highs and Lows

Picture of Highs and Lows
Life can be funny and sad. And by life, we mean the Internet as a whole. But often the text doesn't quite reflect that so we're going to be randomly adding "*sigh*" and "LOL!" to the ends of sentences. Much better now, right?

Source code

Step 5: Sarcasm Enhancer

Picture of Sarcasm Enhancer
Do you really believe everything you read? Whatever. Now the whole Interwebs will be as sarcastic as you feel on a Monday morning.

Source Code

Step 6: What'd You Say?

Picture of What'd You Say?
People keep saying things. All over the place it's so-and-so said this, whatsisface said that. Doesn't anybody shout or enthuse or gush their thoughts?

They do now.

Source code

Step 7: For real

Picture of For real
Ya know?

Source code

Step 8: Watch It

Picture of Watch It
Sometimes the page keeps loading forever...

Source code

Step 9: Dsmvwlr

Picture of Dsmvwlr
Sometimes you don't need all the letters to read the text links.

Source code
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bauerbach1 year ago

The Rick Rollr video has not really been removed.You can still watch it at

applepeave3 years ago
I love the add on compiler. I have made like ten of these and are now looking to unleash them all.... Just need someone to mess with..
This is great, but the link to the all-in-one pack failed to download, and the Rick Rollr link was removed. I tried going to Roll Tube and recompiling the source with one of the other rick-roll videos, but it didn't work at all.

Would there be any chance of this being updated and re-released?
whats the two steps back installment called- i cant fond it to delete it cause its really annoying my bro :)
Thanks for sharing these. So funny. I have played with changing the source code, which is great because I didn't know you could make Firefox add-ons so easily. I'd like to modify the Rick-roll code, but the link to the source seems to be broken. Could you check it please?

fungus amungus (author)  individual1285 years ago
I didn't write that one, but I'm pretty sure this will set you on the right track.

if(Math.random() > 0.8){
   window.location.href = "http://www.google.com";

That's a 20% chance of your window being sent to the google page. Tweak the number between 0 and 1 for odds of it happening and the URL for the target video.

Since many sites have iframes for ads, a single page can have 4 or 5 windows load for what looks like one. We ended up with .98 for the value to avoid it being utter chaos all the time.
Thanks so much. Brilliant, it worked a treat. I have set one up to redirect to that mind-numbingly awful batman thing: http://www.youtube.com/watch?v=NrmPehlHK3w

My wife is going to hate me ;)
Really?  Whatever.
gummypaul5 years ago
Don't be messin' with my firefox now. : )
tsk... with my computer you get this prank all the time "sigh" whoa I must have gotten pranked "lol"!


Lol jk.
godofal5 years ago
this is pure evil

im going 2 use those as a late april 1st prank XD

its just that no one reminded me of april 1st....
travisttt5 years ago
How could I change the link the person is sent to? Could I easily bother them with other random links?
OK, I've become slightly smarter and have found where add-ons are stored. Inside of the firefox profile, where can I find this file?
Xxgold5 years ago
How come i cant download?
 Is there any chance we could get the greesemonkey scripts??
the plugins are good but a lot of people i know use Google chrome, which wont support them (but natively supports greesemonkey)
fungus amungus (author)  compgeek_brad5 years ago
I don't have the GM scripts, but the source doe is in each step. Shouldn't be too hard to remake.
Does it only work on april fools day, or what?
Ahh, I guess every day is fine...
no, i downloaded the sarcasm enhancer a few days ago
fruitkid1015 years ago
erikals6 years ago
this 'devils inbox' trick is based on an interesting number in the bible which is 666. The Devil is generally associated with the number, as is a weird character also mentioned in the Bible who we know as 'The Beast'. Who could this character be? We've only to wait and find out.
either michael jackson or rick astley..
or Steve Jobs
we don't know. I told you that.
NamasteNick6 years ago
is it easy to undo?
Yes. Click Tools>Add Ons, then click the 'gmailinboxer' addon and choose Uninstall. When prompted, click 'Uninstall'. Wait until you see a notice that says 'Restart Firefox to apply your changes.' Next to that notice there will be a button that says 'Restart Firefox.' Click that, then wait a while for Firefox to install the add on and open up again.
Wow this is great!! Wonderful. The only I would do is change the rick roll link to this. I like it more.
lol i clicked on the link and it was pretty funny how did u make it? plz tell me
I did not make that. But I did make a similar one.
Here! Enjoy, :)
 Why is everyone acting so annoyed?
i hate you
I will eat your soul. That drove me crazy.
Right-click Firefox`s part of the bar and click maximize and then you can close the tab.
i noticed it moves away from the back button and makes it go back to the same page. but to get out of it really easily, just click the arrow by the back button, scroll down and click the last page you were on.
thats... annoying. i miight change my mates homepage to that.lol.
damn you
lmao that was annoying i just did ctrl+alt+del and ended Firefox cuz it wouldnt go away.....lmao.....
I just did Ctrl+W to close the tab.
I hate you.
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