It's a temporary hair dye styling gel. From Manic Panic's site: DYE HARD® Gel is very easy to use: just place gel on fingertips or on a tinting comb and apply to hair.
Get creative and have fun with it! It washes out instantly so you can't go wrong. DYE HARD® Gel dries hard and holds hair in place. This product does it all - styles, holds, adds color all in one. The DYE HARD® Gel may be used for spiking, tipping, adding a streak dash or splash of color, coloring an entire head. Best thing about the DYE HARD® Gel is that it shampoos right out of your hair with ease. This product is ideal for kids and adults alike who seek "color without commitment".