Umori, the Collector

The harshest deckbuilding tax of its companion cycle, and the one whose reward is also the least imaginative to unlock. Requiring every nonland card to share a single type is brutal: no removal spells beside your beaters, no artifacts next to your enchantments, an entire list flattened into one column of the type line. The discount pays that off along the very same axis it demanded. If you committed to creatures to satisfy the constraint, then creatures get the reduction; the payoff falls straight out of the sacrifice rather than asking you to bridge two distinct requirements. That collapse of cost and reward into one dimension is exactly why exploiting it never took much finesse. You were locked to one type regardless; the mana off the top just arrived.

That tidy loop is part of what forced the whole mechanic to be rewritten. In their original form, companions lived in the sideboard for free and could be cast directly from outside the game once their condition was met, warping construction across every format they touched. The errata added a flat just to move the companion into hand before casting: a tempo tax stacked atop the deckbuilding tax, and that second cost is now written into the reminder text here. The 4/5 body was never the problem; it closes games while it discounts them. The trouble was the free extra card, and the fix has shadowed this Ooze ever since.