Aliasing feral_druid -> feral druid.

Reason: Same thing, except these search terms are easily combinable to find what you need.

To prevent double tags from happening.

No. A Feral_Druid is a class/specialization in WoW. So pics that depict feral droos from that game should have a Feral_druid tag.

It should say feral_druid_(wow), then.

But, what other sorts of feral druids are there?

character:donatello_(TMNT) is labeld with (TMNT) because there are other (or could be) donatello's out there.