Ceramic octopus pinch pot?

What is happening is the arms are drying at a different rate (assuming the clay is the same) than the body. A simple fix might be is to wrap the area where the cracking is occurring with wet paper towels. It will slow the drying down a little so they don't separate. The problem now is how dry it is altogether. You might be better off starting anew. The old clay can be reused unless it has been fired. When things crack off it is very hard to reattach them with a quality patch. Sometimes vinegar can be used instead of water to reattach parts. It sometimes improves your chance of success.