I bought this from superdrug yesterday and I LOVE it! Its by Barry M and called instant nail effects and you apply it over another nail varnish (here I've used Barry M blueberry) and it gives this crackle effect. To be honest I didn't think it would work but for £3.99 I thought I'd give it a go and I'm soooo glad I did. When you first apply it, it just looks black but after a few seconds it starts to crack and gives the most amazing effect. Everyone should own this!
p.s sorry about the messiness, my cuticles get really dry in winter =(