Introduction: Swimming Through Seas in a Manta Ray Costume

Many people have a hard time trying to find their child a costume for Halloween, because it's too expensive. Here is a costume that is eco-friendly and can be made at home as a family project. This instructable was made for my high school project, which was to "go green" by creating a marine themed costume made out of cardboard. Our group chose a reef animals theme, which included a clownfish, jellyfish, seahorse, turtle, and a manta ray. This costume is creative and still saves you money.

Design Brief:
Design and build a marine themed costume made solely out of cardboard without any adhesives. It also had to be made using slotted construction for easy flat pack storage. The costume is intended to fit middle school students (ages 10-13) either for Halloween or a staged show.

          -Slotted construction
          -Cardboard(any type)
          -Flat pack
          -Safe for age range
          -10-13 year olds are target audience

No tape, glue, or any other adhesive
          -Able to be worn as stage costume or for Halloween

Materials:                   QTY               Size
(S1) Cardboard           4                  8-6"x4"
                                                            32"-4"on top, thinner on bottom cardboard
                                                            45"across-thin on outside, thicker on inside cardboard

 Tools:                                                 Use
(T1)Cutting mat                                 Padding to put underneath cardboard when cutting
(T2)Utility knife                                  Used to cut thicker cardboard
(T3)Ruler                                           Used to measure different parts of the costume
(T3) Pencil                                         Used to draw out all parts of costume onto cardboard before                                                              cutting
(T4) Circle template/compass        Used to draw rounded or circular shape
(T5) Scissors                                     Used to cut pieces of cardboard that are thinner and has a                                                                  round shape

Parts:              QTY
(P1) Eyes         2
(P2) Strap        1
(P3) Tail           1
(P4) Body        1              


Step 1: Part 1:Eyes-Measuring and Cutting Slots

1. Measure(T3) and draw(T4) 8 pieces of carboard(S1) that are 4"x6 1.
2. Cut out parts with a utility knife(T2) over a cutting mat(T1)2.
3. Cut slots(T2) 1" in each side of all 8 pieces

Step 2: Part 1:Eyes-Slotting Together

1. Slot 4 pieces together to form a box and repeat so you have 2 boxes
2. Cut(T2) 1" slots on one opposite side of each box

*Note: If you have extra strips of cardboard sticking out, trim it off with scissors(T6)

Step 3: Part 2:Strap-Measuring, Cutting and Folding

1. Measure(T3) and draw(T4) a piece of cardboard(S1) that's 24"x2" 1.
2. Cut out part with utility knife(T2) over a cutting mat(T1)3.
3. Fold 3" on each side

* Note: This measurement is just an average measure so you can adjust it if you need to

Step 4: Part 3:Tail-Measuring

Measure(T3) and draw(T4) a piece of carboard(S1) that's 32" lengthwise, 4" on top across, and growing thinner on the bottom

Step 5: Part 3:Tail-Cutting

1. Cut out part with utility knife(T2) over a cutting mat(T1)
3. Measure(T3) 1" down, then drawing(T4) a square that's 1 1/2" on both sides of the tail
4. Cut out(T2) the 1 1/2" squares

Step 6: Part 4:Body-Measuring

1. Measure(T3) and draw(T4) a piece of cardboard(S1) that's 45" across, growing thin on the outside to thicker on the inside.
Note: the middle(tallest point) should be 19"

2. Cut out part with utility knife(T2) over a cutting mat(T1)

Step 7: Part 4:Body-Cutting Slots

1. Cut(T2) a slot 5" up from the bottom that's 4" long and has a 1/4" width over a cutting mat(T1)
2. Cut(T2) 2 slots that are 3" from the left of middle and are 4" apart and 1" deep over a cutting mat(T1)
3. Repeat step 2 on the right side

Step 8: Part 4:Body-Cutting Slots Cont.

1. Cut(T2) one slot 7" from the end of the left side of the body(P4) that's 2" long (up to down)
2. Repeat on the right side

Step 9: Assembly Part 1

1. Take the tail(P3) and slide it into the body(P4) at the bottom slot
2. You can fold the top of the tail(P3) into the body (P4) to make it stay

Step 10: Assembly Part 2

Take the eyes(P1) and slide them into the body(P4) at the top where there's 4 slots cut (2 slots for each eye) 

Step 11: Assembly Part 3

1. Take the strap(P2) and insert it into the body(P4) where there are two slots that are 24" apart (the two slots 7" from the end)
2. Bend the strap(P2) into the body so it stays

Step 12: Final Costume

Step 13: Extra Notes-Color

If you feel like you wish to paint the costume, be careful because the cardboard will warp. To prevent the costume from warping, paint both sides of the cardboard. In this case however, you may want the cardboard to warp so that the ray has curved wings.