Build a Glowing Brick Jellyfish MOC: Step-by-Step Guide

The short version: this guide walks you through a brick jellyfish that stands 22 cm tall, uses roughly 860 pieces, costs about ¥180 all in and takes around 3 hours to build — a beginner-friendly entry point into ocean-animal MOCs. The two tricky parts are the curve of the dome and the drifting look of the tentacles, and both are solved with trans-light-blue parts plus hose pieces. Add a small light kit and the model glows like a deep-sea jellyfish. The instructions are free on brickplan.cn.

Step 1: Gather Parts and Tools

The core materials are about 300 trans-light-blue and trans-purple 1x2 and 1x4 bricks, 6 hose pieces, 8 transparent round plates, and one light kit (around ¥20). Buy everything in a single order from the parts list attached to the blueprint on the brickplan platform, and try to pick transparent parts from the same production batch so the colours match — mixed batches are where colour differences show up.

Tools are minimal: one brick separator is enough. There are no stickers anywhere in the build, so nothing to apply or line up.

Step 2: Build the Dome

The dome is the jellyfish's bell. Start by laying trans-light-blue bricks into a ring about 14 studs across, then pull it inward layer by layer, with each layer 2 studs narrower than the one below it. Stack 5 layers this way to form the hemisphere. Close the top centre with transparent round plates, and finish the rim with curved slope bricks to suggest the ruffled edge of a real jellyfish bell.

This step takes roughly 1 hour. As you taper inward, rotate every layer by half a stud so the seams stagger — the dome locks together far more solidly that way, and the curve stays smooth instead of stepping.

Step 3: Make the Tentacles and Light Mechanism

The tentacles are what sell the model. Take 6 hose pieces and cut them to lengths ranging from 8 studs to 16 studs — mixing long and short is what makes the arrangement look natural rather than machine-made. Push one end of each hose into the technic bricks with holes on the underside of the dome, and cap the free end with a small transparent round brick as the tentacle tip.

For the glow, tuck the light unit into the centre of the dome. The light passes through the transparent bricks and diffuses evenly across the bell. Adding two transparent round plates at the base of the tentacles helps channel the light downward, so the whole model reads like a bioluminescent jellyfish drifting in the dark.

Step 4: Add a Display Base and Finish Up

Build the base on a 16x16 baseplate. Lay 2-3 layers of dark blue bricks to suggest the deep sea, and leave a circular recess in the middle to seat the bottom of the jellyfish. Route the light switch to the side of the base so you can turn it on and off without lifting the model.

To finish, check that the tentacles are evenly spaced and the dome is symmetrical, then bend the hoses so the tentacles hang in a natural drifting pose. On a desk with the light switched on, the effect is genuinely striking.

FAQ

Q: How many pieces does the jellyfish MOC need?

A: About 860 for the standard version, roughly 300 of which are transparent parts. If you build the simplified non-lighting version, drop the light kit and some of the transparent bricks and you can finish it with around 600 pieces.

Q: What does the whole build cost?

A: Loose parts average about ¥0.19 each on the brickplan platform, so 860 pieces comes to roughly ¥165; add about ¥20 for the light kit and the total lands near ¥180. That makes it one of the cheaper ocean-animal MOCs out there.

Q: How long does it take to build?

A: Around 3 hours for a beginner. The dome accounts for about 1 hour and the tentacles about 40 minutes, so it fits comfortably into an afternoon — a good pick for a first animal MOC.

Q: How do I choose transparent parts that won't yellow?

A: Favour ABS transparent parts, keep the model out of direct sunlight, and store it in a sealed box. The parts list in the brickplan blueprint gives the part numbers for the transparent pieces, so buying to that list in one batch keeps colour variation to a minimum.

Q: Where do I get the instructions?

A: Search for "jellyfish" on brickplan.cn to download the blueprint free of charge; it includes step-by-step build diagrams and the full parts list. The community also has recolour variants in pink and blue that are worth a look.