There are multiple ways an irreducible biological system can evolve. The most obvious one is from a reducible system with the same function, which then lost or modified parts until it was irreducible. Given the looseness in defining what counts as a part of the system and what the function is, identifying particular systems as IC is usually problematic, but their existence is not a challenge to evolution.
Regarding your proposal, I find it too vague to assess very well, and I’m not sure when you’re using terms metaphorically. Speaking generally, however, complex, functional systems are highly unlikely to evolve unless their function is of use to the organism – they’re just too improbable. (On the other hand, it is possible for a genuine parasite to evolve to become part of its host. It’s not common but it has happened on at least several occasions.)