Eh, carcinization is a better ontological fit. Many separate things evolving into the same structure, versus the process of losing electrons and/or structurally degrading.

And it's the version I've actually heard used (multiple times) before now - having looked up 'carcinisation', I assume that comes via 'rustacean' (cf. crustacean), which makes it a bit more contrived and then sort of implies the result is a Rust developer, not Rust itself?

Makes more sense to me that a language/framework/etc. would 'oxidise' to Rust, and someone learning/getting hooked on Rust would 'carcinise'.

But this is all silly and doesn't matter anyway, ha!

The rust mascot Ferris is a crab. Like how go has a gopher.

And, of course, the name "Ferris" comes from being a homophone of "ferrous".

And not only a homophone - they have the same etymology.

Has that existed since day 1? I don't think I've ever seen that before. The gear icon comes to mind, not a crab.

No, it's unofficial.