Hi. I'm a new owner and got my puppy when it was around 8 weeks old. He seemed content enough; didn't bark, didn't bite people, friendly and all that. However, after eating (just before it does it's crapping) it goes really hyper. It starts biting anything and everything at sight - people too. He will even lunge at your face if opportunity presents itself. And right after it "craps", it's back to normal. I was able to deal with that. However, around two days back, it started getting these "agressive fits" again, and not when it's about to crap; just at random times. And he's more aggressive than he used to be. Barks for no apparent reason (even when no one is really close to him or doing anything involving him), bites and jumps like crazy; aggressive to the extreme, I would say so for an 8 week old puppy. These fits last about half an hour to forty five minutes. He's barking at people downstairs as I'm writing this.
Is this normal behaviour? Should I be worried?

Dogs bark, and puppies can be nippy, what some would view as aggressive. Without actually seeing your dog and his behaviour I really can't tell you if your dog is extreme or just exhibiting puppy behaviour.

It's never too early to start training your dog. There are many ways to stop the aggressiveness and the barking.

Cesar Milan has a great book out about being the pack leader in your home, I suggest getting it and following the tips inside.

Hi.
Thanks loads for the advice. Really appreciate it.
However, I've tried "dsciplining" it before. From tapping it on the nose, screaming "no!" and even in the extremes of closing its mouth and saying "no bite!". Nothing works. Every time I try getting my hand near him, he starts jumping, trying to bite it. Honestly, he was cuddling up with me, pefectly calm, and all of a sudden he just starts biting, jumps down starts biting everything. From my fingers to my clothes and legs and arms and even my chin. It's not just me either, it's the other members of the house, too. If I walk away from him, he runs with lightning speed he's never used before and starts biting my foot. He bites the box he sleeps in, goes totally aggressive with the toys I give him. Then after half an hour, he sleeps and wakes up perfectly calm and normal.
Is it possible that I'm feeding the wrong food or anything like that? I'm really desperate to get rid of that bad habit.

This has got NOTHING to do with what you are feeding him. This is a behavioural problem, and yes you should be worried, unless you take care of this right away.

You and your family are not your dogs pack leader. He has already taken that role at his young age. If this is not corrected very soon, you are going to have big trouble on your hands, and he will get out of control. You are not correcting him in the right way, and this will only get worse. He thinks he is in charge. "No Bite" in an aggressive aggrivated tone and energy is going to make him do it even more! Have you noticed this? Of course you have. The madder you get, the more he comes after you, and the bigger fit he throws. I'm sorry to say, that this is your behaviour, not his. You have to think about a dog that is born to a pack. He needs to establish his place in that pack, and right now he's the leader. He will bite you, chew things, throw fits, and basically do whatever he wants to do, because you haven't taken over the role as pack "leader!"

You are wasting your time tapping him on the nose and screaming commands at him. This is only making things worse. Your energy is going right to him. You are angry, or scared he is going to bite you. Of course you are. But that kind of energy is only going to make him aggressive, and make him bite you more! Do you see how it has escalated from the issue with his food, to biting you and throwing fits? It had nothing to do with him having to go outside to poop. Dogs don't reason that way! Dogs only respond to what you teach them--and to positive reinforcement. They will respond to anger or nervous energy given to them by you and other people.

You need to have a calm assertive energy, when trying to teach him to obey calm and assertive commands. Screaming will have the opposite effect. Being aggressive towards him, will have the opposite effect. Don't EVER use his name while giving him commands.

Think about how you might treat a small baby when it does something undesirable. Do you scream at it and tap it's nose, and expect he will learn? Of course not. You need to teach him the right way to do it. Since dogs don't understand "people language," you need to show them through your actions, what is expected of them and what is right and wrong. You can only do this with short commands, and body language. Although you may think that your dog understands your words, he doesn't. He ONLY understands your tone of voice, energy, and body language.

Here is a link that may help you to get better acquainted with training your puppy, and becoming the pack leader. Altenweg mentioned this way of teaching in her answer, and she is right. There are many methods of training, but in my opinion, Cesar Milan explains it very well. There is some very good info. If you start now and stay consistent, you can have a very well behaved dog.

Good luck!

Dog Channel: Cesar Millan

My puppy has been doing something similar, except she will just have fits where she won't want to be held or touched and all she does is cry. She saw the vet today, and I think its just her being cranky. I ignore her when she acts like this, and she calms down. Its probably not helping too much, but at least I am not rewarding her with more play.