You can make a mold of the tail using "Plaster of Paris" and non-stick oven spray. Old rubber baits, in the color you want, can be microwaved and poured into the mold. Then trim both the swimbait and tail you made and glue back together using a Mend-it type of soft glue. Check YouTube for a demo. But have an adult help with the hot plastic because it can be over-heated to high temps that can burn the heck out of a person who isn't careful. Eye and hand protection is a must.