---
# System prepended metadata

title: Metadata & NFTs

---

# Metadata & NFTs
## Why Metasaurs is a complete fuckup
**Tl;dr: [Metasaurs](https://twitter.com/metasaurs) fucked up their community by handpicking some tokens and changing their metadata to rank on top of rarity.**

We love and NFTs and we are super excited for the fact that this movement is empowering so many underappreciated artists across the world. 
Sadly, this is not what our first article is about. This article is about the darkside of NFT and how some creators abuse the faith their community puts in them.
You see, we at RankRadar believe in transparency. Our ranking system is designed to automatically parse the metadata revealed by the creators and output a rank that is algorithmically generated. We welcome collaboration with the creators to better reflect their intent, but overall we believe the community deserves transparency regarding what happens with their assets.
### Enter metadata
Metadata is a link, an URI(https://datatracker.ietf.org/doc/html/rfc3986) to be more exact, towards a resource. Behind that URI there is a Json file, hopefully formated by the ERC 721 standard(https://eips.ethereum.org/EIPS/eip-721) that provides all the funky details about your ape, seal or lion. 
What happens most of the times is that projects prefer to mint the entire supply before revealing the metadata. This means that you don't actually know what is behind the token you've just minted until the creators call a certain "method" from their smart contract. That method is "Set Base URI" and it changes the main portion of the URI.
### This is too technical, why do I need to know this?
Fair point, we did have to give a small technical introduction so that this next part makes sense. 
A few days ago, on the 17th of October 2021 a collection called [Metasaurs]([https://twitter.com/metasaurs](https://)) was set to reveal their metadata. At the request of one of our Alphapass holders we monitored it. After a few delays, 6 hours later, the metadata was revealed and we went on with the rest of our day. A few hours later, we noticed something strage, the metadata we parsed a few hours later, wasn't matching the current metadata for just a few tokens.
### The digging
So we started to investigate and figured out that the metadata had indeed changed, but in a weird way.
The base URI was changed for the whole collection twice. ![](https://i.imgur.com/zR7Uk1J.png)
The first Set Base URI txn is this: 
https://etherscan.io/tx/0x8ddb53d6adbedb3101d4836613afdba1313dd413fd50f96f699c6a92931fdf90
and it did this:
![](https://i.imgur.com/qwLdGnl.png)
Te second Set Base URI txn is this: 
https://etherscan.io/tx/0x08ce13d0dbd8dc60fde65ddc565e0d4bdffa0ec4851719b5c65eb50f4b25a5c1
and it did this:
![](https://i.imgur.com/hJbdWUA.png)
(When you check the transaction, make sure to go down to "Input Data" and press "Decode Data")
That in itself is not a big problem, since issues can arrise during a reveal, so we started checking the metadata for random tokens:
If you compare this: https://mtsr.mypinata.cloud/ipfs/QmfFjEKs8jt1FszxuYweFjPA3nGmNC7zAEnJ2Am519MsNE/8337.json
with this:
https://mtsr.mypinata.cloud/ipfs/QmbbA4AVHkP9vZnQZ59VVj4LzmWGXbCd6Tpwg4MyR9kkdv/8337.json
one would notice there isn't much difference, apart from some formatting. Understandeable if the metadata in the json file is not formatted properly, the collection developers might change the Base Uri in order to correct those issues for all the tokens in the collection.
However, we started looking at the rarest token from that collection, namely #279
The first metadata looked like this:
https://mtsr.mypinata.cloud/ipfs/QmfFjEKs8jt1FszxuYweFjPA3nGmNC7zAEnJ2Am519MsNE/279.json
Nice, but nothing too special about it. However, the new metadata looked like this:
https://mtsr.mypinata.cloud/ipfs/QmbbA4AVHkP9vZnQZ59VVj4LzmWGXbCd6Tpwg4MyR9kkdv/279.json
Completely different and actually the rarest of them all.
We have reached out to the collection and asked 1 simple questions. Why does the metadata look identical in both cases for the vast majority of tokens, with only a few radically changing?
We still haven't received any answer on this, so we decided to publish our findings so that more people can ask the same question. Maybe we'll finally get a plausible answer. 
