Gather your supplies. You'll need:
*40-ish melty (perler, hama) beads
*An old ponytail holder
*Small scissors

Next, you'll want to make a small slit in one of you beads. I found that the best way to do this is slide the bead onto the scissors (as shown in the picture) and snip down.

Now open the bead as far as you can....

and pop it onto the ponytail holder.

Repeat steps 2-4 until you've filled up the whole ponytail holder, and there you go!

Make as many as you want! :)
and btw, the amount of melty beads you'll need depends on the size of the ponytail holder you're using. My rainbow one was made out of a ponytail holder that was pretty streached out, so I think I needed closer to 40, while my other one was pretty small, and only needed about 30.