The Four Sons of Horus aren't the only gods who live in jars or bottles. Their containers, called canopic jars, are actually named for the Greek demigod Canopus. We're not sure how this group gets together without being accidentally thrown into someone's refrigerator.
This is the guy who gave the Four Sons their archaeological name. Canopus was once the captain of King Menelaus's Spartan ship during the Trojan war. Sadly, on one of their voyages to Egypt, Canopus died of snakebite. The local people put Canopus's ashes in a jar, renamed the city in his honor, and the king built a monument there before leaving for home. Eventually, the Greek citizens of the city named after Canopus worshipped him as a demigod, using his jar as their symbol.
In Eastern Europe, when people wanted to honor Mother Earth, they put a bit of her body—the dirt of the ground—into a jar and kept it in their homes or buried it outside their houses. Mat Zemlya would be good to your family as long as you were good to her.
This Greek god isn't actually in a bottle, but with the way he drinks, maybe he ought to be. He makes lots and lots of wine for his wild parties, and it's said that his cup is never empty. The Four Sons aren't allowed to attend any of his parties. Horus the Younger doesn't want any of their contents to be pickled, on top of mummified.