Woodweaver's Puzzleknot

Energy is the odd resource: it lives entirely in the player's pool rather than on any permanent, and this artifact is the cheapest, plainest faucet for it. The payout comes in two loads. Half arrives the moment it lands (three life and three energy with no further input), and half waits behind a green-mana activation that sacrifices the artifact for a second helping of the same. A bare three life for two mana is filler; the reason to run this is the deferred second batch, gated behind color and mana so you cannot draw both loads for free. The card lingers as a promise you cash in later, and you hold the second activation not because energy grows more valuable (it does not, since energy never drains from your pool once banked) but because cracking it costs mana you would rather spend elsewhere. You sacrifice it on a turn with spare green and a sink to feed. The life is incidental, a sweetener that occasionally matters against an aggressive opponent but is never the point. What the design rewards is a payoff that turns raw stored energy into an advantage worth paying the activation for; without one, the artifact is three life and a permanent you never bother to crack. It is a supply line for a mechanic that has surfaced across multiple eras without ever settling into the game as a permanent fixture.