Ghost Gadget: press its head, up go the arms!

A little sheet ghost with a secret. Push down on its head and both arms swing up at once to give you a friendly peace sign. It's a fully mechanical Halloween desk toy that goes together without screws.   Highlights Fully mechanical: a hidden rack and gear inside the body, no electronics. Both arms on one shaft, so they always move together. Easy to print: every part is already oriented, and the few supports it needs are tiny and easy to remove. Snap-in eyes and a press-fit rack: no glue needed. Two arm styles: one finger or peace sign, both with draped sheet sleeves. Step-by-step assembly guide included as images and a PDF. Size: about 95 mm tall and 68 mm wide with the arms. The head travels 10 mm when you press it. How it works When you press the head, the body slides down over the legs. A rack on the legs turns a gear inside the body. The gear sits on a single shaft that runs straight through the body and carries both arms, so the arms swing up together. A small rubber band pulls everything back when you let go. A stop disc on the shaft sets the resting position, so the arms always drop back to the same place.   What you need Printed parts (1 of each) Body: `ghost_body.stl` Legs: `ghost_legs.stl` Rack: `ghost_rack.stl` Gear: `ghost_gear.stl` Stop disc: `ghost_stop_disc.stl` Shaft: `ghost_shaft.stl` Eyes, both in one file: `ghost_eyes.stl` Arms, one pair (L + R) in the style you like: One finger: `ghost_arm_L_--.stl` + `ghost_arm_R_--.stl` Peace sign: `ghost_arm_L_peace.stl` + `ghost_arm_R_peace.stl`   Not printed 1 small rubber band, about 40 mm around (roughly 13 mm wide when relaxed). A regular office band works too: tie a knot in it to make it shorter. Printing Supports: turn them on. Only a few very small supports are needed, and they come off easily. Keep the orientation from the files. Recommended settings: PLA, 0.2 mm layer height, 15 % infill. Walls: use 3–4 walls for the gear, stop disc and shaft so they stay stiff. Shaft: it prints lying on its flat side, which makes it strong along its length. Colours: a white body with black eyes looks classic. A glow-in-the-dark body is even spookier! Assembly Follow the guide images; there is one picture for each step. Left and right always mean as seen when you look at the ghost's face.   1. Eyes: push each eye's peg into its hole in the face until it clicks. The eyes are mirror images, so if one won't sit flush, swap them. 2. Rack: press the rack's peg down into the socket on top of the legs, with the teeth facing the heels. It's a press fit, so no glue is needed. 3. Gear, stop disc and shaft: - From below, hold the gear (left) and the stop disc (right) between the side walls, in line with the side holes. - Push the shaft in through the right-hand hole, flat side down: through the disc, then the gear, and out through the left wall. - The disc's small arm must point toward the face. 4. Arms: push the arms onto both shaft ends, R on the right and L on the left. The holes are D-shaped, so each arm fits only one way. Both arms hang straight down. 5. Rubber band: - Slide the legs into the body from below, only part of the way. - Hook the band over the two pegs at the back of the body. - Pull only the upper strand up into the groove on the back of the legs. The lower strand stays under the legs, so they can't drop out when you pick the ghost up. 6. Legs in: push the legs all the way up until the rack's teeth catch the gear. Let go, then press the head. Both arms go up!   Troubleshooting The arms don't lift all the way: pull the legs down until the rack lets go of the gear, then push them back in. The shaft won't go through: turn the gear or the disc a little until the D-shaped holes line up. An eye won't sit flush: swap the two eyes. The rack feels loose in the legs: make sure it's pushed all the way into the socket. The small ribs on its peg need a firm press. One continuous D-shaped shaft through the gear, the stop disc and both arms, so the arms can't slip against each other. Guide rails inside the body keep the rack straight, even when you press the head off-centre. Longer heels keep the ghost from tipping over when you press it. The rubber band routing keeps the legs in place when you lift the ghost.   🎃 Made for the MakerWorld Halloween 2026 Design Contest. If you print one, please post a make. I'd love to see your ghosts!