When I was younger I had watched a film about a guy that found some alien black seed or something like that. It somehow stung him and he built a small antenna or something like that, then he started behaving like an alien and transporting that seed in order to bite other people. I believe the movie was mid or late 90's, and I' m pretty sure it has a sequel. Anyone help, I'm looking for it everywhere.

Sounds like,.

Robin Cook's
Invasion

Absolutely! They were rocks and not seeds, and the movie is just so long that seemed to be 2 parts played together when I saw it. Thank you very much, I've been looking for it for ages!