DIY Block Monster Costume: 30-Min Cardboard Build

DIY block monster costume built from solid-color sweatsuit, any color, large cardboard box, and packing tape

AI-generated concept photo

Time30 minEffortEasy

⏱️ We timed it, but results may vary.

Plan this costume →No signup · 2 minutes.

One solid color head to toe, foam or cardboard blocks squared onto the shoulders and limbs, and a hand-drawn pixel face. Thirty minutes, easy: a solid-color sweatsuit, a large cardboard box, and packing tape. The square silhouette matters more than the face. Blocky shoulders sell it.

3 of 5 things covered, counting basics we assume you have.

Tap a supply to tick what you own.

Still need:

SweatsuitRed face paint / lipstick

Update my pantry

Tip: edge every block with silver duct tape.

Sizing: Built for teens and adults. Have each wearer step into the box before you mark arm and leg holes, cut them a little wide, and tape every inside edge so cardboard never scratches.

Materials

Solid-color sweatsuit, any color, 1 set (own)
1 large cardboard box (make: cut it into square blocks)
Packing tape, 1 roll
Scissors, 1 pair
Non-toxic face paint, 1 tube (buy: toy store)

Steps

Cut the box into square blocks: two large, four medium.
Test-hold each block against the body before taping.
Tape one large block to each shoulder.
Tape one medium block to each forearm and shin.
Pull on the solid-color sweatsuit under the blocks.
Safety: Keep the face paint clear of the eyes.
Draw a blocky square-toothed grin with the face paint.
Optional pro finish: edge every block with silver duct tape.

Start this costume in the planner

Common questions

How do the blocks stay on?

Packing tape loops: tape the block to the sweatsuit sleeve or pant leg with two strips. Tape sticks to fabric well enough for one evening and peels off after.

What size blocks for a small kid?

Halve everything: medium blocks become the shoulder blocks. Oversized blocks on a small kid drag and bump doorways.