There are a new type of eggs for the UBs found in each Ultra Space. Pointless gimmick, but the "eggs" have codenames:
>Nihilego: UB Void (shapeless blob)
>Buzzwole: UB Protein (looks like a giant blood cell)
>Pheromosa: UB Molt (looks like a roach egg sack)
>Xurkitree: UB Bulb (mix of a plant bulb and lightbulb)
>Celesteela: UB Shoot (looks like Celesteela's arms)
>Kartana: UB Seed (you've already seen it)
>Guzzlord: UB Feed (looks like a spiked rubber tire with teeth in the center; unlike other eggs this can be interacted with in Refresh and fed)
Pichu also has a unique egg design now, so it looks like they're experimenting with the idea that's been shown since Togepi and GS promotional art.