Leyline Tyrant

The floating red mana clause is the whole engine here, and it inverts one of the game's oldest housekeeping rules: mana empties from your pool between steps and phases, so ramp usually has to be spent the turn it appears. Strip that restriction away and mana becomes storage. Every untapped red source across a turn cycle can pool into a reservoir, and this Dragon converts that reservoir into a burst of face damage the moment it dies. The design tension is that the two abilities want opposite fates for the creature. The retention line rewards keeping it alive across turns while you stockpile; the death trigger only pays out once it leaves the battlefield. That makes it a threat opponents are punished for answering: point removal at a 4/4 flier and the accumulated pool can discharge into a player's face, so the card asks removal-heavy decks whether killing it is worth eating the payload. The timing wrinkle is subtle: once the Dragon dies its static retention clause is gone with it, but the triggered ability puts a spend-any-amount-of-red outlet on the stack right then, letting you cash the banked pool before the phase ends and it empties. It sits in a small lineage of red cards that treat unspent mana as a resource to bank rather than burn, but most of those were rituals or storage artifacts. Wrapping the idea around an evasive body that fights on two axes at once is the design's real contribution.