Experiment - have the Stalkers eat Peepers when they are nearby. Previously this wouldn't have worked, as our creatures were spawned willy-nilly all over the world. But now we "leash" creatures to a home position which generally keeps creatures from interacting with each other unless the player gets involved (similar to Don't Starve). So while Stalkers and Peepers generally won't spawn too close to each other, if you can lure a Stalker near some Peepers, he will eat every last one of them, then return to his home position. It's a start... - Charlie