The bulk update request #11717 is pending approval.

create alias skulldog (12) -> skulldog_(disambiguation) (0)
change category skulldog_(disambiguation) (0) -> invalid

Reason: The term skulldog can either refer to skulldog_(artist) or the species that the artist designed, skulldog_(species). The wiki entry currently already functions as a disambiguation, directing users to the other two tags, so moving it to a disambiguation would be in line with its current usage.