The Key Item Azure Flute, which would allow a holy encounter with Arceus, was never legitimately released to players.
However, found within a file (decchi.bin), that was found in Generation 4 distribution carts for Deoxys, (Uploader's note: file-ception at it's finest)
It appears that an Azure Flute distribution was being tested via slot-2 distribution.
The nature of the slot-2 distribution game that this wonder card was obtained from, only allowed distribution to JPN games.
The distribution text seems to be reusing the distribution text for a Generation 3 Old Sea Chart distribution.
It was also discovered by @Deoxyz that changing the distribution type from Key Item to Pokemon, will show complete information for an Infernape to be received.
It was also discovered by @DeadSkullzJr that the copy of the wonder card in the game (seen via hex) slightly differs from the wonder card that was received. The one in the game has a redistribution count. Presumably this copy has the redistribution count, but the received one does not, because it does not allow players who received a copy to redistribute.
The Key Item Azure Flute wonder card (.pcd), Modified to show Infernape (.pcd) and the Infernape (.pkm) are up for download.
[We will not host the decchi.bin or Distribution Roms for the Deoxys]
Gen 4 Decchi - Azure Flute.pcd - Extracted from save that received it. The one without redistribution count.
Gen 4 Decchi - Azure Flute (Hex Extracted, Redistribution count).pcd - Hex extracted from the game. The one with redistribution count.
Gen 4 Decchi - Infernape.pcd - The receiving type was modified to show the Infernape gift hiding within
Gen 4 Decchi - Infernape.pkm - A pk4 file of the extracted Infernape.
Wonder card Images
Mystery Gift Test
Do accept this gift from Friendly Shop (?)
Let's bring the Old Sea Chart to the Faraway Island! (Ikuzou!)
Let's go to the wild Mew!
While this wonder card will activate the event, the Arceus right now can be considered illegal and legal.
Do note it's possible to obtain a Hall of Fame Arceus via Tweaking, and it'll pass Pokemon Bank when it's Level 100,
but that can be easily changed, if they decide to block it.
Use at your own risk.
Images regarding Infernape: