Today I joined in to Crono's Minecraft server. He and other PGR friends made amazing buildings, and I went to his tree farm in the cellar/basement of his house.
First, I farmed trees with one of his diamond axes (he's got diamond pickaxes and diamond shovels, too). Then, I discovered that there's also a PGR 'headquarter'. But suddenly, the aggressive mobs came. A skeleton attacked and hurt me in the PGR headquarter, and spiders attacked me outside. Even a creeper came and the attacks seriously injured me!
But fourtunately I could get rid of these ******* and I felt better.
And finally, before I disconnected to the server, I saw two creepers who dropped into a very deep chasm.
This chasm could be a mob trap.
And when I play Minecraft beta 1.8 not in peaceful mod, I'll be scared of Endermens, because these are IMHO even more dangerous than creepers! Spiders also look and sound scary.