The harvester trick obnly works with the nod harvester. Be some character and charge out into the opening. As the nod harvester comes out of the tiberium, run behind it and keep running forward into the back of the harvester. Stay a little to the rigth of the back and keep doing this ytil you're about 10 feet from teh obelisk and run inside the obelisk as quick as possible. Plant c4 on hte master control terminal and say goodbye to teh obelisk.The mammoth trick involves making a mammoth tank disappear. I've done this in game accidently and it proves not so useful but funny anyways. Have one guy buy a nod transport vehicle or "the nod apc" and have the other guy buy a mammoth. Go to the first rock on the left as you come out of the nod base. havew the mammoth's front end be against that rock and the back end facing the wall. Wedge a "nod apc" behind the mamoth and have the apc try to wedge more and trhe mammoth try to escape (which it cant) after a little bit of time one of three thing will happen. The mammoth tank will disappear, or the apc will disappear, or both wil disappear. The result of this is either the driver returns to the base as if he just died, or the driver and his vehicle are put somewhere out in oblivion in their vehcle twirling faster and faster. I've done this once during an actual g ame and the guy's mammoth disappeared.. he was ****ed. But i can easily replicate it now.