This is a parasitic plant, belonging to the family Taxillidae, mostly widely parasitic (Taxilli), mainly spread by birds. If we leave it alone, carambola will absorb all the nutrients and die in a few years. If you want to save this carambola, you'd better find relevant people to artificially remove a large area of parasites or treat it with drugs.
I hope my answer can help you * _ *!
This is what a broad parasitic flower looks like: