Expecto Patronum is a significant spell used in Harry Potter movies charm conjures a magical guardian, a projection of all your most positive feelings. The charm will produce a shape of an animal or something you're sharing more affinity with.
Presenting here the Ethereum as the shape produced by our patronas charm, it's conveying the protection/ guardian for us from all the evils which lights the whole 'Diagaon Alley' (The gateway to the wizarding world).
Ethereum itself is the best representation of patronas charm if any of us would be producing the charm.
If taken from another perspective, The Resurrection Stone, one of the fables in deathly hallows, represents the exact figure of Ethereum.  It owns the power to recall its holder's loved ones from death.
So further we leave it to the audience to relate the resurrection stone to Ethereum.

In a conclusion, everything we see around
This magical movie can be related to Ethereum as it is the same magic that happened to the web3 world. The miraculous change it brought over to the artists in every nook and cranny of the world. The light that Ethereum brought to everyone who believes in it made the same perfectly relate to this particular movie.
