They weren’t quite as organised as Militant but there was a clear semi-coordinated push by ex-corbynists on social media in particular to join the Greens in the shambles of Your Party’s first bambi-like steps before it hemorrhaged its brains after falling.

I’d say this was definitely entryist in attitude, to take an existing party and flood it with new activists that would attempt to strong arm the party’s democratic structures to their own ends. I don’t think there’s anything wrong with it per-se but I think entryism describes what was happening.