I was exploring a mega taiga, collecting moss stone. As I destroyed a boulder, I thought I saw something moving in a tree. I looked up, and saw a brown form behind some leaves. Deciding that it must be a cow that spawned up there or something, I went back to mining.

As I kept walking through the forest I saw more brown things out of the corners of my eyes. Surely there weren't that many cows in trees!

Suddenly, something hit me from behind. Turning around, I saw a spider-ish creature, with no head and legs all around its body. I hit it back, and it scurried up a tree.

I started running through the forest. More spider-things jumped out of trees and chased me.

A redstone contraption came into view. I tried to go away from it, but the creatures herded me into it. Smoke started coming through the floor, and then a firework rocket came out--taking me with it into the air! Then it exploded, displaying the message "Buy at MooTech!" and I fell to the ground and died.

If you see brown shapes in trees, get away from them as fast as you can.