Thoroughly wash all radishes. Pat dry.
Cut leaves from the radish. This slice will make a nose, so be sure to keep the cut small. Cut off one side of the radish to make for a stable bottom.
Use the cut from the bottom to make the ears by cutting a small V into the slimmer end. Cut a slice on top of the radish to hold the ears. You may need to angle the slice so the ears lean back. Trim the radish root to about the length of the radish for a tail. This step may not be necessary as many radish roots are usually sold with triimmed roots.
Cut two small X's for eyes on the head of the radish mouse. Dig out enough of the radish flesh with the tip of the knife for the peppercorns, and then push the peppercorns into the cuts. If young kids are helping, you may want to do this for them as they may take out too much of the radish.
Make a slice near the back of the radish for the place card. You may need to angle the cut so the card doesn't pitch forward.