Euclid, as I assume you are aware, was also the name of the first dude to write down a significant textbook on geometry, hence the irony in that something which shares his name defies the very laws he set out in his famous work.
SCP-1504 is Joe Schmo, who seems to be a very unremarkable, and hence, unmemorable human who is invulnerable to most damage, and whose actions are also notoriously hard to remember.
