Creature Lab
A student designs a creature and watches it come alive. Underneath the fins and the colors is one rule, repeated down a chain of points, and out of that rule comes swimming, slithering, and walking. Free, in the browser, no account needed to try it.
What a student actually does
They shape a body, add fins or legs, choose colors, and drop food in the water. The creature swims, hunts, hides, or walks. A first creature takes about five minutes. Nothing is scored, there is no timer, and nothing is lost by experimenting.
What makes it more than a toy is that the movement is not an animation. Nobody drew a swimming fish. There is one rule in the program, "stay exactly this far behind the point in front of you," and the swimming, the slithering, and the whipping tail all fall out of that rule. Change the body and the movement changes with it, because the movement was never separate from the body.
The same creature, twice. On the right is what it is really made of: a row of points, each one holding a fixed distance behind the point ahead of it. Students can switch to this view at any time, and most of them do.
What other students have made with it
Every one of these was built by a student on the platform and published by them on purpose. Click any of them to open it.
What they are learning while they play
Nothing here is presented as a lesson. This is what the activity is made of.
| What the student does | What it is |
|---|---|
| Sets a rule that every point must stay a fixed distance from the next | Distance on a grid. The same coordinate geometry they will meet again in algebra. |
| Watches a change at the head ripple all the way to the tail | Iteration. A loop that runs the same small rule down a list, which is most of what a computer does. |
| Makes the body stiffer or floppier | Constraints. A limit on how far each joint may bend. Loosen it and you get a snake; tighten it and you get a fish. |
| Turns the creature toward food | Angles and direction. Measured in degrees, relative to the way the creature is facing. |
| Gives it legs and watches the feet stay planted, then step | Inverse kinematics. The genuine technique used to animate game characters and to control robot arms. |
| Turns on behaviors like "hunts food" or "afraid of tank-mates" | Sense, decide, act. The loop underneath all programming and robotics. |
| Writes a program for the creature's brain, in blocks or in JavaScript | Conditionals, variables, and debugging. "If food is close, turn toward it." When the creature misbehaves, the program is wrong and they have to find out why. |
| Gives several creatures the same simple rules | Emergence. Two rules about keeping close and keeping apart produce a school of fish that nobody programmed. |
How to tell whether it landed
Ask, and let them show you. A student who has understood it can answer these without help.
- What is your creature actually made of? (Ask them to show you the Bones view.)
- Why does the tail move like that when you turn?
- What would happen if you made it more flexible? Try it and see if you were right.
- Why do its feet stay in one place instead of sliding along?
- Show me the rule that makes it go after the food. What would you change to make it ignore food?
Practical notes
- AgesAges 8 through high school. Younger students design and play happily; older ones go further into the skeleton editor and the programming.
- TimeFive minutes to a first creature. A satisfying session is twenty to forty minutes.
- EquipmentAny computer or tablet with a browser. Nothing to install, no plugins.
- CostFree. The app has no paid tier.
- PrepNone. Open the page and go. Reading this page first takes about four minutes and is worth doing before handing it to a student.
- In a groupA whole group can put their creatures into one shared pond and watch them interact, which works well in a co-op room.
For co-ops, microschools, and classrooms
The part that turns a quiet room loud is the shared pond. Every student releases their creature into one tank, and the group watches what happens when eight animals with eight different sets of rules meet each other. Predators chase, schoolers pair off, and somebody's overtuned flexibility slider produces something nobody expected.
- One shared pond per classroom. Students keep editing their own creature and the pond picks up the change.
- No install, no lab setup, no per-seat license. Chromebooks and tablets are fine.
- A free teacher account covers up to 50 students.
- Student work is private by default. Sharing anything publicly is a separate, deliberate action.
Common questions
Is Creature Lab free?
Yes. The app runs in your browser and there is no paid tier of it. A free account adds saving, sharing, and the shared class pond, but nothing on this page is behind a paywall.
Does my child need an account to try it?
No. The demo on this page is the complete app, and it saves your work inside the browser tab so you can experiment freely. An account matters only when you want the work to survive closing the tab, or when you want to put a creature in a shared pond.
What ages is Creature Lab for?
Ages 8 through high school. Younger students design and play happily without touching the programming. Older ones go into the skeleton editor and write the creature's brain in blocks or in JavaScript, which is where the real computer science lives.
How long does it take?
About five minutes to a first creature. A satisfying session runs twenty to forty minutes. There is no timer, nothing is scored, and nothing is lost by experimenting.
Does it install anything, and will it work on a tablet?
It installs nothing. It runs in any modern browser on a computer, a Chromebook, or a tablet. There are no plugins and no downloads.
What subject can I log this as?
Most families log it as computer science or as math. The distance, angle, and coordinate work is geometry; the creature's brain is programming with conditionals and variables; the legs and gait are engineering. The table above lists specifically what is covered, so you can pick the label your records need and point at the evidence.
Can a whole co-op or class use it together?
Yes. Every student's creature can be released into one shared pond that the group watches together. That needs free accounts and a classroom, which a teacher or co-op leader can set up in a few minutes.
Is my child's work public?
No. Projects are private by default. Publishing to the public gallery is a separate action a student has to take, and public listings mask the display names of younger students.
Where to go next
Start with Creature Lab
Trying it costs nothing and takes about five minutes. An account is what makes the work last.
Creature Lab is one of the making apps on the platform. It is a place to make things, not a course, and it is not a substitute for a teacher: it is at its best when an adult asks the questions above and takes the answers seriously.
The animation technique is based on argonautcode's animal-proc-anim, used under the MIT license. Source.
Page last reviewed August 2026.