Sometimes spray paint cracks and it can look really cool! It’s good to know how to get the effect and how to avoid it. The cracking has to do with the cracked paint being thinner than what is underneath it. It also has to do with how wet the first layer of paint is.
To get cracking, use a layer of thin spray paint on top of semi wet thicker paint. It may take some time to fully crack.
In the US, one brand that can create cracking is Molotow. If you use it on top of a thicker and wetter layer of paint, many times you get some lovely cracks.
To avoid your paint cracking, make sure the first layer is thin and dry before adding thinner more dry paint on top.