This is a useless thing to have. It create useless sparks. You can also make this use less thing to scare other people. This is not really dangerous.but can set any flammable thing on fire easily.you can watch the video of sparks.

Stuff you need!

high voltage capacitor (I used 2 for increasing my capacitance)
any power adapter (voltage grater then 5v and less then 18v)
cardboard
wires
diode.

tools you need!

hot glue gun
soldering iron
a pair of scissor

basic idea!

we will charge some capacitors and discharge them to make sparks.

Step 1: Wiring!

For competing of this step you need a hot soldering iron some pieces of wire and the component mention in first step. You need to follow the systematic given above.

EXPLINATION!

we use the 12v source to charge the capacitors. We use a diode in between to restrict the current coming for capacitors as it can easily damage supply. then we have two wires out of the negative and positive of capacitor as it is electrolytic capacitor polarity matter a lot.

finding the polarity!

Here we have small tip. The side of capacitor having strips like pattern is negative side of capacitor.

Back to point you can see that I have used two capacitor in series this is because I want to increase the capacitance of over all system. I have used some dab of hot glue to join the capacitors.

Step 2: Putting in a Box.

I use some cardboard to make a box to put every thing inside it. you can also make a box according to size of your capacitors. Then fit your capacitor or in my case capacitors and use hot glue to close it then use some tape. Cover the box with paper and make it look fancier you can add strikers to it to make it look more dangerous looking at the end I have add two nails and stich them to that box to.

I have tried it on my suspect known as steel ruler and I got some pretty serious sparks. The camera result is really bad forgive me. You can see the video given in first step to see the sparks I got.

Uses:

in the title I have named this as useless thing but I got some things whish we can do with this. We can ignite any flammable material easily such as methane or perfumes

Disclaimer:

as thing is really dangerous so disclaimer is necessary.In case of any bad thing happened by using this stuff

I will not be responsible of any of your loses.