This will require a little basic knowledge of balloon twisting but you tube is an excellent source for twisting information. I am going to show you how to make my Angry Birds Pig.
You will need a hand pump, a black marker Sharpie or Galaxy brand, a lime green 260 twisty balloon, I prefer Qualatex brand. You may also need scissors or a pin is helpful too but if you know how to break balloons that will not be necessary.
If you are familiar with making balloons this is simply a pig minus the body.

Step 1: Start Twisting!

Pump your balloon up about half way, no need to waste the rest of the balloon. You will want to burp it so that it is soft. This means you let just a little air out so that it is no longer firm, it will have a little give to it. Tie it off. Now start out with a tulip, or apple twist (same thing, different name). To do this you need to move down about three fingers or more and stick the tip of your index finger into the nozzle, so that you are putting the nozzle inside the balloon, once done you take your fingers of your other hand and grasp the nozzle inside the balloon and twist to secure (don't let go). http://www.youtube.com/watch?v=gC9HL72zwXQ&feature=fvsr Now make a five bubbe chain, small bubble, a medium bubble, a small bubble, a medium bubble, a small bubble, a medium bubble. small are going to be about 1 inch and mediums maybe 2 inches. Twist the first and last bubble together then pull the snout through. Those two small bubbles you made need to be made into pinch twists. http://www.youtube.com/watch?v=eYoOi0oIEWM These are the ears. You now need to twist a small pinch twist, or two your preference, on the bottom. Break the rest of the balloon off.

Step 2: Draw the Face and Fight!

Now you have a pig without a face! Drawing the face for the pig is simple he needs nostrils, eyes, and any mouth you want to give him, or leave it off your choice. Nostrils are the easiest, simply draw two ovals or solid lines on wither side of the 'dent' in his snout. Next the eyes, round circles with dots in the middle go above his nose on his brow. The mouth goes beneath the snout in any form you want.
Now that he has a face you can pit him against your angry birds!