Add stalking AI to bugs

[PrayingMantisTerry]

I think bugs are scary in this game, but aside from nearly flying out of my chair after accidentally running into a bug’s detection range and triggering the scary music, I think there should be some sort of way for the bugs to, like a lion, stalk their prey—especially the praying mantis and different spiders. Imagine how cool it would be (and admittedly scary) to get snuck up on by a spider or praying mantis. If you catch them stalking you, they could just switch back to the default AI. Also, mantises are pretty buggy—they keep getting stuck on the leaves when trying to jump down.