No, not "an enormous pile of evidence", but maybe some in eukaryotes suggesting bits of DNA transferred between very different kinds of critters -- horizontal gene transfers aka gene hijacking.
Natural mechanisms for it include viruses which are today employed in state-of-the-art gene therapies.
Alberta's Child: "How could a clownfish possibly evolve without a fully-formed sea anemone in existence?"
No idea why this seems so challenging to you.
Occam's razor suggests the simplest explanation possible which would be some time in the distant past when those sea anemones had no poison and clown fish used them for cover.
Over time anemones develop increasingly poisonous cells and clown fish increasing immunity to them.
Any anemones without poison get killed by other predators and any clown fish without immunity get killed by anemones.
Coevolution is the term.
1. A sea anemone uses its poison to kill its prey. How did it eat when it had no poison?
2. A clownfish is brightly colored -- to attract other fish to the sea anemone. How does any living creature develop physical characteristics through an evolutionary process that have no benefit for itself but have tangible benefits for another organism?
3. Why has only one fish -- the clownfish -- developed this way? Shouldn't we see multiple species that went through a similar process?
4. Is there any evidence of either creature existing in its interim evolutionary stage as you've described it -- i.e., a sea anemone with no poison and/or a clownfish that wasn't immune to the poison?
5. You've completely misrepresented the principle of "Occam's Razor." Occam's Razor suggests both of these creatures were formed at the same time in their current state.