You obviously are confused. A transitional creature is a fully formed and functional creature. Otherwise it would'nt live to reproduce.
The key point is that a transitional creature has an ancestor and a descendant that show a progression of evolutionary changes. Like much of the fossil record. Saying all fossils are transitional creatures is an overstatement. Some of them died out, the rest ARE transitional.
This is pure, baseless speculation. Again, the fossil record typically (always?) shows creatures entering and leaving the fossil record, over great periods of time, with the same morphology.