Print body and shell separately in color you want and in horizontal position. Use support when you print shell.
Snail has eyes and mouth in black color on one side. To achieve that use color change option in your slicer.
Shell should snap on body without glue.
If you want eyes and mouth in color on both sides you have to cut body on 7 mm height. Then copy part with eyes and mouth and and mirror it. After print you have to glue two parts teogether.