Merfolk Raiders
Half the time, this Merfolk doesn't exist. The body phases out before your untap step and stays gone through your opponent's turn, which means it can attack and block on exactly the turns it happens to be present and does nothing on the rest. Durability is the payoff: while phased out, the creature is untargetable, immune to sorcery-speed wraths, and safe from removal, returning the following cycle as if nothing happened. The islandwalk stacks a second layer of evasion on top, slipping the body through unblocked whenever the defending player controls an Island. The problem is that you don't set the timer. The window of invulnerability arrives on its own schedule, and so does the window of presence; you can't line up either with the moment you actually need it, and the proactive trick still depends on the opponent obliging by keeping an Island in play. That bargain (rigidity traded for survival, on a creature that surrenders agency over when it can act) is exactly why the keyword struggled to find a home. Wizards circled phasing for years, judged that it confused more than it rewarded, and shelved it for a long stretch before reviving the mechanic on terms it could better control. The card is honest about the deal it offers: a creature that is hard to kill precisely because it spends half the game refusing to participate.
