Mishra's War Machine [Antiquities] Gnome Creatures it was blocking that

Creatures it was blocking that had become blocked by only that creature this combat become unblocked

Then each player reveals their chosen card

where X is the difference

When Sidisi

Mishra's War Machine [Antiquities] Gnome Creatures it was blocking thatSet: Antiquities Type: Artifact Creature Juggernaut Rarity: Rare Cost: {7} Banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.) At the beginning of your upkeep, Mishra's War Machine