I'm grateful to be part of this, too!
Some plants are parasitic and able to get their
energy and carbon from other plants. Mistletoe is
a fairly well-known example of a parasitic plant:
it grows into other plants, usually trees, and
extracts everything it needs to survive from the
tree that it is living on. There are many other
kinds of parasitic plants as well.
Of course, the host plant does need light, and
if it dies, then so does the parasite, but the
parasite itself doesn't need light as long as the
host remains alive.