Shroomy
Adventurer
The newest Primal Power excerpt is up and it covers the swarm druid (though there are some hints about the druid paragon paths), which, as it names suggests, allows the druid to become a swarm of insects or vermin (its favored by druids from the jungle and Underdark). It looks interesting, though I hope there are some poison powers or feats, because it really fits the theme. BTW, we will be seeing the return of an old favorite, creeping doom to 4e.
Primal Power Excerpts: Swarm Druid
Primal Power Excerpts: Swarm Druid