Prerequisite: Personally defeated a possessed neo-biological unit while in operation of a tandem pilot semi segmented autotomical defense unit.
When you spend an action point you may activate the Action Swarm power either before or after the extra action by spending the action point. When you take this feat you must specify the type of swarm you create. This selection is permanent and can only be changed by retraining.
You become a swarm of smaller creatures totaling two times your maximum number of hit points. While in this form you cannot use any other powers or activate any magic items in your possession, but you may still interact with other things as normal.
While in this form you become a large creature and gain a climb, fly, burrow, or swim speed equal to your current speed as appropriate to the form, selected when the feat is taken. Also you can occupy all and enemy squares while in this form.
While in this form you have vulnerability 10 to close and area blast attacks, but resist 10 to all other forms of damage.
Enemies that start within the swarm take 5 damage per teir and can be the target of an effect that any of your at-will attacks would deal besides damage.