I think dman_dustin and others are right: Cosmog will evolve into Cosmoem at the end of this episode, as a result of Faba using its powers to open an Ultra Wormhole. As dman_dustin said, that's precisely what happens in the games. Additionally, the summary for SM51 states that Ash seeks out Hala's advice in part because Nebby won't move. That sounds to me like Cosmog has evolved into Cosmoem and is immobile because of it.
That's assuming Lusamine was actually aware Gladion had stolen Silvally prior to today's episode, and it seemed she wasn't. In fact, given what I understood of the conversation between her and Gladion, it seemed she wasn't even that familiar with Faba's "Beast Killer" project. She may not have been aware of what Type: Null was actually created for. She can't have much attachment to a creature whose existence she barely remembered, so she would have no reason to be angry with Gladion for stealing Silvally.
