Someone at Ikea should've spotted this...

...but, appparently, it's been there for months.

Hammerhead

I took a trip to the thrift store for this costume, and bought two large grey sweatshirts, one with a hood, and a plain white t-shirt. At a craft store, I bought a rectangle of styrofoam, poly fill, and a 8 1/2 x 11 sheet of white foam. Any other bits and pieces that wound up on the costume are things I had around the house.

For the head part of the costume I cut out the top part of the hoodless grey sweatshirt. I hot glued it, stuffed it, and added the eyes, then hot glued the head onto the hood part of the other sweatshirt. I drew it out to give a better (I hope!) visual.

I cut out foam teeth and attached them around the opening of the hood. I wasn't going to add the red mouth opening, but my costume wearer got a case of shyness at the last minute, so I cut an oval out of some red fabric I already had, hot glued it around the hood opening, and cut holes in for the eyes.

I cut a fin shape out of the styrofoam. I then covered it with the grey fabric from the cut up sweatshirt, hot glued it together, and then hot glued it onto the back of the costume. I cut out long strips of white t-shirt and glued them along the side to look like the gills, and cut a big oval white piece to be the bottom part of the shark's body.

Who You Gonna Call?

For this Ghostbusters costume, I bought a light tan sweatshirt from the thrift store. Then, using iron-on transfers, I applied the Ghostbusters logo onto the right sleeve and "Venkman" on the upper left chest.

The power pack is a giant cardboard box that I spray painted black. I cut an opening around one side and slid a backpack into it, creating the straps for the pack. I found a bunch of Ghostbusters decals online and printed them onto labels which I cut out and placed on the pack. Any bits and pieces sticking out of the pack are things I had around the house: old toy car tires, plastic containers, etc., that I spray painted black and glued onto the cardboard box.
The utility belt was a toy plastic construction worker belt that I found at the dollar store. I spray painted it, then attached various ghosthunting "tools" onto the belt with clips. The ghost-catcher box is from the dollar store; painted black, with yellow electrical tape on one side and a warning label that I found from a Ghostbuster site online.

The goggles are just regular safety goggles. I found this pair in the garage.

I probably spent less than $15 on the entire costume, and I think it looked pretty good when it was done.