(Manually created. I can't use the alias suggestion tool for this, because semi-anthro is already aliased with semi_anthro.)
Aliasing semi-anthro → invalid_tag
Reason:
It breaks the current standard.
This tag group is complicated enough without adding an another tag to it. If we keep this one, we'd have to start using tags like anthro_on_semi-anthro, etc. And keeping it brings up all kinds of problems, such as whether human_on_semi-anthro is bestiality, etc.
Better to just keep the current standard of pigeonholing them into either anthro or feral. Sure, that's hard sometimes, but keeping this would only make it overly complicated.
Updated