Breeding is almost here!

7 min readOct 14, 2021

We’ve been hard at work for the past few weeks designing and building out the breeding phase of the Anonymice project.

Side note: Sorry it’s taken us so dang long, we‘ve heard that some devs could do all this in a day ;)

When we first launched Anonymice (just a month ago!) we had a simple goal of doing everything 100% on-chain. We also wanted to prove that we weren’t doing this as a cash grab, so everything was free with 0 royalties.

How it started. I posted this in the Cryptopunks discord because I figured that was probably one of the most watched channels for new projects.

Another side note: It looks like we might have “invented” this minting concept so can I name it?? I’d like to call it “tokenized minting”. You read it here first :)

Since launch we’ve done over $40 million in secondary sales, our floor has held strong around 9ETH, had some real-life meetups (NYC party coming up!), multiple murals painted around the world, and a very active and exclusive alpha community for owners:

Owning a mouse gets you access to the exclusive #mice-alpha channel in our Discord

We got a ton of great feedback from the community as we built out the mechanics for breeding. We are still on track to launch on 10/15. Our breeding launch process will be really unique and community oriented and I hope you enjoy it.

We’ll announce the launch on Twitter and Discord.

But seriously, I really don’t want to ruin anything or give too many hints, just make sure you’re paying close attention to our Discord and Twitter on 10/15.

Here is more detail on how we built breeding and some of the mechanics. There will be more to explore and we’ll dive into even more details over the next few weeks, but for now this should give you a pretty clear idea of how Anonymice Breeding will work…

The Basics

  • Baby supply: 3,550
  • You need 2 Anonymice to breed. You can buy them on OpenSea
  • It costs 50 CHEETH to breed 1 baby
  • It takes 7 days (50,000 blocks) for the baby to be revealed
  • The 2 parents are time-locked for those 7 days (50,000 blocks)
  • You can speed up the reveal or the time-lock by depositing CHEETH into your breeding ticket.
  • It costs 25 CHEETH for a full 7 day speed-up of the baby (0.0005 CHEETH speeds up 1 block)
  • It costs 25 CHEETH to speed-up the 7 day time-lock of the parents (0.0005 CHEETH speeds up 1 block)
  • No cost curves, no limits to how many times a mouse can breed

Pure On-Chain

This is the part we are most proud of. Everything is done through our smart contracts. We have no APIs, nothing is on IPFS, no external dependencies at all.

This has been our core philosophy since day 1. We understand that pure on-chain isn’t realistic or possible for all projects, but we want to show off what is possible with a little ingenuity. We were able to pack all functionality into just 2 smart contracts.

That being said, we have put together a simple frontend that you can use to interact easier with the breeding contract. This will make it easier to go through each step of the breeding process. We’ll post the link to this when we announce breeding.


We are choosing to maintain 0 royalties on our original Anonymice collection and launch with 0 royalties on the Breeding collection. We are discussing internally the possibility of adding a future royalty with the sole purpose of funding community projects to keep building out the Anonymice eco-system.

As devs, our intention has been, is, and will continue to be that we only profit from the appreciation of the NFTs that we continue to hold. We did no early minting and have no advantage in breeding over anyone else. We’ll be farming and breeding along with everyone else.

Breeding Costs & Timeframe

This part was really hard. There are infinite ways we could design the cost and mechanics of breeding. At the end, we decided to keep it as simple as possible.

Breeding timeframes are based on blocks but we’ll use days to keep it simple.

50 CHEETH to breed. ~7 days (50,000 blocks) to reveal the baby and unlock the parents.

The baby reveal and parent unlock can be sped up for 25 CHEETH each.

It costs 0.0005 CHEETH to speed up 1 block (~13 seconds). So 1 CHEETH will speed up about 7hrs. 3.5 CHEETH will speed up about 1 day.

You can do speed-ups at any time for any amount. Please be careful to calculate how much CHEETH you actually need so you don’t overspend.

If you want to breed and reveal and unlock as quick as possible, it will cost you 100 CHEETH.

If you sell your incubator, the new owner can then spend CHEETH to speed it up.

Since each mouse generates 1 CHEETH per day, this means you can breed a pair approximately once per month. It will take you 25 days to generate the necessary CHEETH and 7 days for the reveal/unlock.

You must do a transaction to unlock the parents and a separate one to reveal the baby.

What this means is that you could actually sell an unrevealed incubator and the owner could then instantly reveal it. All of this will be in the metadata for each token and can be refreshed on OpenSea. You will also be able to filter the incubators on OpenSea to see which ones can be revealed the soonest.

Genetic/Non-Genetic Traits

Your babies are much more likely to have one of the parents genetic traits (base mouse/mouth/nose) vs non-genetic traits. One exception is that Glitched and Irradiated have lower likelihood of transfer.

OG Advantage

If you breed with an OG mouse (#0–1999) you have a slightly higher chance of generating a rare base mouse.


We wanted to include something a little extra to make the breeding process even more exciting.

So we created: Legendary Baby Mice.

There are 9 different 1 of 1 baby mice that can be generated by any incubator. There are no special bonuses, every incubator has the exact same chance. Each time you reveal a baby, you have a small chance of generating a Legendary.

The first 3 Legendaries each have a 1% chance of being generated (1 in 100).
The next 3 Legendaries each have a 0.5% chance (1 in 200).
The final 3 Legendaries each have a 0.3% chance (1 in 300).

They are all generated in order. So when the first Legendary is generated, the next one will be different, and so on… until all 9 are minted. We’ve run multiple simulations and this distribution creates a ~98% chance that all 9 Legendaries will be minted by the time the 3550th baby is revealed.

Mouse Tinder

It will be possible for the community to create a decentralized method for single mouse owners to breed. We won’t be building this out but we also won’t be designing our contracts to stop it.

However, there is one really important exception:

We won’t allow contracts to reveal the baby mouse. This is being done to stop someone from writing a contract that could attempt to mint Legendaries unfairly (i’m looking at you hype.eth).

You can ask around in the Discord to get more info on this if you are a single mouse owner and still want to get involved in the Breeding process.

What’s next?

Once we launch Breeding, we are going to start planning the next phase of Anonymice. No we won’t build a fancy roadmap graphic, no we won’t tell you what we are planning. We’re just going to work hard to build something even more awesome than what we’ve done so far!

We’re also going to start building out a community led team to keep adding even more value and utility beyond what we as the founders will build. If you’re interested in being part of this core team, please DM us on Discord. We’ve had a ton of fun building this out so far, and we’ve got some more things we want to build….but we’re also blown away by the size and quality of the community that has come together so quickly. We’ve got designers, builders, coders, artists, strategists and everybody else in between! We’re laying the foundations that the community can build on to make Anonymice into something awesome, inclusive and enduring.


Ok this is a lot to process. And I’m sure you have questions that aren’t answered here. Please jump into Discord with any questions. We’ve got a great community that can help you out.

We (the two people that make up MouseDev) plan to take a little break once breeding is live. We’ll still be around and hanging out in Discord (and breeding our mice!) but we gotta give our minds a little rest.

We ❤️ ️you.


PS: if you see anything weird or any errors please message us on Twitter or Discord.

PPS: just before I published this post, we found this website: Check it out!




On-chain, generative NFT. Free to claim with defi mechanics. We don't have a website, just a smart contract.