Supposedly someone uploaded a Doom clone to the bitcoin blockchain:


But I'm a bit confused on exactly what is uploaded using "Ordinals". From a quick read of Ordinals, I'm assuming they are just using OP_RETURN and putting in a encoded string into a block or a transaction?

This encoded string uploaded is a "id" that links to a file on ordinals.com? So technically no real files are uploaded like this Doom clone is it? And if ordinals.com is offline, none of these files are accessible?

And how is this different from colored coins or counterparty from about a decade ago?

2 Answers 2


Ordinals Inscriptions don't use OP_RETURN, they are embedded within the script of a taproot input. It's not just a link to a file on some website, the entire file is actually published to the blockchain.

The embedding is done using data pushes inside an unexecuted script branch like so:

(embedded data comes here)

You can view the script from your specific example here: https://scriptpath.info/tx/521f8eccffa4c41a3a7728dd012ea5a4a02feed81f41159231251ecf1e5c79da
It consists of 59 pushes of 520 bytes each and one push of 73 bytes.

  • So that Doom clone is exactly how big on the blockchain and how much did it cost? Feb 2 at 16:59
  • 520*59 + 73 = 30,753 bytes. The transaction adds another 445 bytes of overhead for a total of 31,198 bytes (but, because of the witness discount, only 7870 virtual bytes). The fee paid was 19,675 sats. Feb 2 at 17:45
  • How to decode this (embedded data) using bitcoinjs ? Feb 10 at 15:40
  • 19k sat-fee. In other words, the cost of putting doom inside block 774526 was ~46$USD.
    – Paul Kania
    Feb 23 at 18:52
  • Any reason why they split the data in 520-byte chunks?
    – DeLorean88
    May 9 at 15:12

The MIME data type of that inscription is text/html;charset=utf-8. So maybe it is something like Doom in javascript

Ordinals inscriptions do embed the data in transaction data that occupies space in the Bitcoin blockchain.

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