Swarms

[Stygofthedump]

Core only Druid lv 11. I'm considering how I can use rat swarm and rat form. Some kind of mirror image effect? Add in fog for concealment maybe as swarms ignore concealment. Any way to get around DR?
How about giant vermin spell and wild shape into 'giant' bat?

Any ideas?

[nedz]

If you summon a swarm of rats using Summon Swarm, and then inhabit their area, even if you are also a rat, they will attack you.

Bats are Animals not Vermin, otherwise I don't see any synergy between Giant Vermin and Wildshape; other than maybe you could get the enemy to play the shell game somehow ? But that's about Bluff, which isn't a class skill for you.

[Necroticplague]

Technically, you can already do this. A Rat Swarm is a Tiny Animal, even if it takes up a 10x10 space. So you could turn into one at level 8. Of course, you wouldn't gain most of the benefits, due to not gaining the swarm subtype (since Wild Shape is based off Alternate Form, which doesn't give you subtypes).

Meanwhile, even while wildshaped, you retain your original type, so Animal Growth still won't work on you. You also can't turn into templated forms, so you can't turn into a creature with a template that makes it bigger. However, Dire Bats are large, which is pretty much what you seem to be looking for. Some Desmodu Bats are even bigger (I think the Demodu Soldier is Huge), but those aren't core.