Fen Stalker

Tapping out is the whole idea here. Most evasion in black asks you to pay extra or commit a keyword to the card itself; this one hands you fear for free, but only while no land you control is untapped. The condition reads like a drawback until you trace the turn cycle backward: spend your mana for the turn and the 3/2 picks up fear, slipping past everything but black and artifact creatures; untap on your next turn and it goes back to being a vanilla body until you commit your mana again. The card rewards the exact board state aggressive decks naturally arrive at (an empty mana pool, nothing held back for interaction) and turns that tempo into evasion. It belongs to an early-era experiment with abilities that read the state of your lands, caring whether you had tapped out the way this Nightstalker does. The body is fragile and the condition is a genuine leash on any deck that wants to keep mana open for tricks or counters, which is why the card never escaped its niche. But the underlying idea (evasion priced in tempo rather than mana or a permanent keyword) is sharper than the stat line lets on: the same resource you spend to advance your board is the one that switches the evasion on.