Catalyst Elemental

The body is a receipt for mana you plan to spend elsewhere. This is a 2/2 you never intend to defend: it walks onto the battlefield to be cashed in, and the proposition is arithmetic. Pay three mana for a fragile blocker now, sacrifice it later for a two-mana burst of red exactly when a combo or an oversized spell wants the extra pips, and you have effectively stored mana across turns while a vulnerable creature marks time in between. That deferral is the whole design lever. Unlike a one-shot ritual that has to be in hand on the turn it matters, this sits on the board accruing options: an attack, a chump block, or the eventual sacrifice, and it never asks you to draw it into the right window because it is already there. The wrinkle is that the sacrifice is the activation itself, so the card doubles as fodder that happens to leave mana behind. It feeds a sacrifice engine, pays a convoke or emerge cost, seeds a graveyard, and each of those uses fires whether or not you ever collect the two red. It is an enabler built to die on your terms, and the is the payment for a creature that was always meant to be spent.