* Snail whispers: "Hey, Crabby! I saw you digging in the sand earlier. Whatcha lookin' for?"
* Snail calls out: "Excuse me, Mr. Crab! Do you know where I can find some delicious seaweed?"
* Snail uses a leaf as a phone: "Hello? Hello? Is this the Crab hotline? I'm stuck in this shell and I can't get out!"
Let me know what kind of story you want to write and I can help you come up with some more ideas!