This mani is courtesy of my next door neighbour, who swooped into my house brandishing her new bottle of Miss Sporty Crack Me Up polish, painted my nails with it, then ran away laughing before I could take a picture of the bottle.
Unhelpfully, I can't seem to find a stock photo of it anywhere, either. So here's a helpful link to the Boots.com website, whereupon you can gaze upon the black version of this polish (you'll just have to picture it in blue, I'm afraid).
Pictured is one coat, over Rimmel Your Majesty. Like all crackles, it dried quickly to a matte finish (I added a layer of top coat to make it shine). Compared to other crackles I've tried, the crackle effect is a bit more hit and miss. One finger on my other hand didn't crackle at all, and my ring finger on this hand crackled kind of strangely compared to the other nails.
The cracks also tended to be mostly vertical - not so many crosswise cracks as I saw with the Barry M Instant Nail Effects and Rimmel Crack Your Colour. It was quite sheer, too, which I thought made for quite a nice effect over the silver Rimmel as it turned the blue colour metallic :)
Wear wasn't the best - I had chipping by the end of the day, although this might have been because it was over a manicure that was already two days old, so I wouldn't write it off as an easy chipper until I'd tried it again. Overall, I liked this a lot more than I thought I would - I wasn't that keen on blue crackle until this, but actually it was a pretty nice shade of blue and looked rather festive, especially with the shiny metallic effect it gained from the silver base.