Odin performed the spell to invoke his primordial god, to ask him to end the Greek gods and thus the Nordic Pantheon would reign over the rest, and therefore him, would reign above the rest of the gods in Heaven... but instead of that god... you appeared

Odin:...

Huginn: Who are you!? You are not a primordial god! Muninn: What happend, Lord Odin? Did you make a mistake when performing the spell?