Before I post anything, I know this has already been posted by someone ([Only registered and activated users can see links. ]). But I did this quite recently and have done did it again today. Also he lost his mystery box.
1. Enough points to use the box about 8 times
2. Know what the Power-up glitch is
3. Fire sale
1. Do the power-up glitch a few times
2. Get a fire sale
3. Use the box until you get the teddy bear
4. Use the fire sale
This will take a while to get but it works. Don't have any evidence but try it out yourself before you flame.
Done, so know you should have two mystery boxes. Sometimes the mystery box that gets the teddy bear doesn't work or only works once.
VERY IMPORTANT: THIS GLITCH DOES NOT TO MY KNOWLEDGE INCREASE YOUR CHANCES OF GETTING RAY GUNS OR THUNDERGUNS. ALL IT DOES IS CREATE A SECOND BOX THAT MAY OR MAY NOT WORK.
Can't make a video tutorial but its simple enough to do it. I can try and get some photos but I'm kind of sick at the moment :( . The power up glitch can be found here. [Only registered and activated users can see links. ]
But in a simpler tutorial, the instructions would be:
1. Get someone to prone next to a wall or in a corner.
2. Sprint at them
3. Just before your about to hit them do a dolphin dive
4. You and your friend should be downed
5. Your other friend now revives you
6. Repeat steps 1-5 a few times, your friends should take turns diving
7. You now have higher chances of getting power ups e.g. Nukes, carpenter, firesale, double points