According to the lore text at the bottom of the card, the creatures are trapped on a rock (possibly an asteroid.) Someone left behind an encrypted log recording the existence of slivers, either an unlucky explorer or, perhaps, a scientist involved in experimenting with the creatures, which would be a nice callback to the Riptide Project
The theme here is consistent: if you are willing to invest in a longer game where you stretch your Stage Two plays through turns 5, 6, and possibly beyond, Orzhov is going to reward you with cards that are good against both conventional attacks and predictable control elements
2022 World Championship Decks Revealed for March
Theyre played by putting them on top of the illustration section of the original card, so you can still see the original card text but the BREAK image looks like the card illustration
not only that but he also got an alternate art leader card in this set