Shield bubbles!

[Kenshaiso]

See I was thinking a shield bubble would be good - obviously it would come at a huge power cost and possibly tie into drawing more and more aggro from the biters. Also, to make it less OP some kind of flying biter/biters that will spawn either as a kind of mobile biter nest/brood mother or just large numbers of normal ones as have already been suggested.

Short term defense against large biter attacks
Perhaps give it a short lifespan or long recharge rate, with huge power costs.
Make it that once its on, its on and cant be turned off or picked up.
Must have a certain level of stored energy to activate
Nothing can pass though it - even the player
Some other stuff I forgot