What you'll need:
1 large "punching" balloon with a rubber band attached.
cardboard for making horns and head feathers (cereal boxes, etc)
green card stock for eyes
2 sheets white copy paper for mouth
blue crepe paper
bright yellow/gold crepe paper
red crepe paper
black sharpie and/or black poster marker
red poster parker
lots and lots of adhesive tape (for wrapping presents) - I used 2 rolls for this project.
candy and prizes of your choice
silver mylar tissue paper (for confetti inside) or packaged paper shred for presents
bowl for holding the form upright
This went much faster than the Sonic Boom piñata. I finished this project in about 6 hours, not including overnight drying time.
UPDATE (2/10/14): This pinata lasted a long time at the party this weekend! We had to strengthen it before hanging with some gaffing tape wrapped around the body - there was so much candy in it, the rubber band wasn't even close to strong enough to hold the filled pinata. Instructions adjusted in that step below. It was also a big hit - it tore but didn't break completely until about 8 kids had given it one good whack each with a wiffle ball bat.
Step 1: Building the Body
For this piñata, I used a punching ballon that comes with an attached rubber band. This means a built in hanging device. These also blow up larger than a standard latex balloon. I blew it up really big, afraid it would pop in my face at the end. As with Sonic Boom, I used cardboard to form the horns and his little feather-like items on his head. I tape everything securely and applied the papier mache.
UPDATE: After putting this into use, I discovered that the rubber band isn't nearly strong enough when you weight the pinata with candy. I suggest using strong gaffing tape or duct tape to wrap around the first layer of mache, looping it around the bottom of the shape and extending it past the top of the body to make a loop. You can then loop this tape around a bungee cord hook or loop rope through the tape loop to hang it.
Step 2: Mache Away! (but Don't Forget the Trap Door)
After my first layer dried, I had some sagging places where the balloon had pulled away from the mache overnight. I used wadded up and slightly wet newspaper to fill in those spots and then used strips to cover over and hold them in place. For the second and third layers, I concentrated on the lower part of the cavity, to ensure that the piñata would stand up to several good hits before breaking open. Also concentrate on the area around the rubber band in the balloon, because you're going to need it to be sturdy when you cut the balloon loose.
BEFORE adding your second and third layers, cut a small square of cardboard (about 4" x 4" and tape it to the layer of mache about 3 inches behind where the rubber band comes out of the balloon. This will be your "trap door" to put treats into the piñata when it's dried and ready to fill. Don't tape this door to the balloon, because you're going to pop the balloon after your layers have dried!
Step 3: Covering the Horns and Head Feathers
I used glue solution to cover the feathers on the top of the head. At the end, I used a hidden tape technique (roll the tape onto itself and stick it on the back of the crepe, then use that to affix the crepe to the item, leaving the tape hidden) to add another layer of red and blue crepe to cover the glued on crepe. The glue solution dried slightly white on the red and blue paper.
Step 4: Add Crepe Paper to the Body
Starting at the bottom of the piñata, begin taping the slit blue crepe paper around the base. Because you're doing a mostly round object, you can just wrap it around and around, adjusting it to slowly begin covering the entire form. When you get to the level of your lowest pair of horns, you will need to cut and tape the crepe paper in place. Keep on the same level and tape a piece between the horns, to give the effect of continuous "feathering" on the critter. Keep taping around, until you've got nearly the entire thing covered all the way to the top.
Step 5: Opening the Trap Door and Deflating the Balloon
At this point, continue adding your blue crepe paper, BUT don't tape it all down over the trap door. Determine how much you need to cover the door in your layers of crepe, and then leave one end unsecured. Cover the rest of the head all around the trap door, but just let those layers for the door hang loose for now.
Step 6: Making the Face
For his eyes, I used the remainder of the bright green card stock I used for Sonic Boom's eyes, and colored in pupils with highlights to show his crazy eyes. The eyes and mouth were taped on with the hidden tape technique.
Photo of Wrecking Ball from: http://static3.wikia.nocookie.net/__cb20111107201861/spyro/images/5/55/Wrecking_Ball.jpg
Step 7: Filling Wrecking Ball's Belly!
Once you have the goodies inside, tape down your trap door carefully. Now, you can also use the hidden tape technique to secure the blue crepe paper layers to cover the door.
Put your piñata in a cool place to keep the candy from melting until you're ready to have some fun!