This is something that actually brings up a lot of interesting questions in Christian theology. A lot of Christian thinking specifically centers around humanity and the special place that humans have within the world, having “rational souls” and being “made in the image of God.” Therefore, it is not impossible for other beings to have been made with this formula, but it does raise a lot of questions. I think the multiple Incarnations is the most interesting possibility. Christians believe that God took on a human form as Jesus and shared his message with mankind, and I think the stance of the Catholic Church would be that this is a singular event - after all, it is considered so significant that we still use it as the basis of our dating system to this day. Aliens talking about crab Jesus probably wouldn’t be the end of the world for Catholicism though. After all, God is supposed to be all powerful and so if He decided to become a man to save mankind there’s nothing that would prevent Him from becoming a crab to save crabkind. I would still lean towards the Catholic church deeming that crabs must accept human Jesus and that their crab Jesus teachings are false, akin to Krishna beliefs encountered by missionaries in India. That said, Catholics also believe that Catholic teaching is so fundamentally true that it is possible to arrive at a lot of Catholic principles without Jesus having taught them, and so they would probably focus on how close the Crab Jesus religion is to Catholicism to try to convert Creezus followers to following Jesus.

Is this intentionally referencing, or unintentionally recreating a large chunk of the plots of the Ender’s Game series, after the first book?

carcinization

“You aliens have Jesus, too?”

“Yeah, he showed up 1900 years ago. Ushered in a golden age of enlightenment and prosperity. He checks back on us every century or so and provides new advancements is philosophy and theology. We’ve lived a utopian existence ever since. Why do you ask?”

“He only ever visited us once and hasn’t been back since.”

“What did you guys do when he arrived?”

“Uh… errrr…”

“And why do you all wear big plus signs on your clothes?”

“Ho-boy, this is awkward”

crab nebula
crab people
crab jesus

Astro-theo-carcinisation

As an enjoyer of fringe content it is pretty common lore that the Vatican is involved with UFOs

The testimony comes from a highly credentialed intelligence whistleblower that came to Congress to basically say “there’s a money black hole sucking up the defense budget and no one knows about it because it’s for black projects, and oh yeah UFOs”

Fun fact, in addition to that Pope Francis made a comment saying he’d baptize aliens:

“Who are we to close doors? In the early Church, even today, there is the ministry of the ostiary [usher]. And what did the ostiary do? He opened the door, received the people, allowed them to pass. But it was never the ministry of the closed door, never.”

and from Grusch’s claims (Wikipedia)

"documents reporting a spacecraft of alien origin had been recovered by Benito Mussolini’s government in 1933 and procured by the U.S. in 1944 or 1945 with the assistance of the Vatican and the Five Eyes alliance. "

But I don’t think there’s any actual trail for hinting a pope saw an UFO sadly

This is very very loosely the plot of The Sparrow by Mary Doria Russell. They weren’t sent to necessarily convert the aliens, but the Catholic Church were the only ones willing to bankroll a trip that would take at least 60 years and have no possible ROI.

It definitely does not go as planned and, maybe unsurprisingly to modern readers, ends with the Catholic Church being cast as a bunch of perverts in the public eye.

That image goes hard