You can use any shape. It doesn't have to be a bunny. Just trace a shape or cookie cutter. This would be cute for any holiday, just use an appropriate cookie cutter to trace and cut out the shape, then whatever yarn works best for that holiday!
Use craft items to make a funny face at the front of the jar. Fill it with dirt and grass seed. It's so funny to watch the hair grow under the sunlight. Should you enjoy arts and crafts you really will really like this site!