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Into the Night and Unnatural Moonrise can quickly transform your team, too

When the creatures are imbalanced and the spells are terrible, midrange dominates

Enchanted creature gets -X/-0, where X is the number of cards in its controller's graveyard

The card's total weight, its center of gravity and, ideally, the moment of inertia (which implies a homogeneous distribution of mass on the surface)

Its also one of the more mentally taxing mechanics for paper tournament play, since a revealed Companion puts the onus on both players to regularly verify that the condition is not violated (something that seems likely to become an accidental issue post-sideboarding in draft)