Like the topic said, design your own devil fruit power.
Please don't make the devil fruit power way too outstretched.
And remember, have fun!
My own Fruit:
Name: Bat Bat Fruit, Model: Macroderma gigas(Ghost Bat, largest carnivorous bat species in the world)
Effect: The ability to transform into human-carnivorous bat or full carnivorous bat.
Notable: Ability to perform sonic transmission. Considered within carnivorous category, thereby increases user's body size. Human/Bat has the physical appearance of a vampire. Able to fly.
Attack: Sonic Expulsion: Super Sonic waves. Critically damaging eardrums. Direct brain damage.