Omega biters and spitters

[baronvonfritz]

At max level pollution and max sized hive, I'd like an omega level/gigantic sized alien that just walks through walls and needs 4+ max bonus'd gun turrets, or 3+ max lasers, or 2+ flame throwers to take it down. It'd be a nice incentive to keep your local area clean and keep the pollution level down. Upon killing said monster, it should also drop some artifacts. The omega spitter should have an area of effect spit to make up for its lower HP. The omega biter should have massive HP or when it dies it drops a mess of big biters.