Grab an old take-away container to start. Any old container will do! Reduce, re-use and all that!
Get an old bit of cardboard and use some tape as a stencil to draw a circle onto it. Then draw another freehand circle around that and cut it out.
Find something soft (or anything that Mum and Dad won't mind you poking a hole in!) and place this underneath the card circle for protection. Then use some scissors to poke a hole through the middle of the card. This will make it easier to cut out the middle part of the circle. Then repeat the same again so that you can double layer your circle to make it thicker.
Tape both of the circles together using some shiny tape. Then use this to draw around your circle onto your box. Cut out a separate rectangular piece of card and tape around this to make a controller!
Tape up the lid of the box, being careful not to get in the way of the lid closing! Try and avoid the circle that you have drawn, but don't worry if you go over it slightly - it doesn't have to be perfect! Then get some different coloured tape and add on top to decorate. Yellow is great as it looks like hazard tape! Stick on your taped circle using some glue.
Next you need to make your controller look awesome! You could use something like masking tape on it because you can write on that!
You can add extra decorations to your box at this point. We added some old batteries as handles. Tape one on each end of the box and then cover the whole box in metallic tape again, leaving a small square at the bottom of the box. Then use some yellow tape to decorate the sides of the box.
Add any extra details onto the box that you fancy by drawing on it. You could even print some symbols off from the internet and stick them on. Then your box will be done! YAY! But what about that blank space you left at the bottom of the box?! Well that's for shining your phone light through to make your slime light up - AWESOME!