Arrester's Admonition

The Addendum keyword rewrote the math on a bounce spell that had been priced as a standalone tempo card for most of the game's history. Straight three-mana creature removal-to-hand is a losing exchange in a vacuum: you spend a card and mana to delay, not to answer, and the creature comes right back. The reward clause here refuses to pay off at the moment tempo actually matters. Cast it on your own main phase and it replaces itself with a fresh card; hold it for the opponent's turn, where a bounce spell earns its keep by blowing out an attack or resetting a just-resolved threat, and you get the bounce alone. That is the tension the design is built around: the card asks you to choose between the effect's best timing window and its best rate, and it will not give you both. Addendum as a mechanic does this across a whole cycle, but the pull is sharpest on an effect whose entire value proposition is instant-speed flexibility. Return-to-hand at sorcery speed is a tempo-neutral cantrip; at instant speed it is a tempo swing with no card advantage. Same three mana, two completely different jobs, and the spell forces you to commit to one before you know which the game will call for.