Sigiled Sentinel

The redirect clause carries the whole trigger. When the enters ability puts its +1/+1 counter on another creature, that creature borrows vigilance until end of turn; keep the counter on the Sentinel itself and the vigilance is redundant, because the body already has it, so the trigger collapses into pure stat growth. That fork is the entire decision the card asks on the way in: pump the newcomer into a 3/3 attacker, or hand a swinging teammate the ability to hold the line and race in the same turn. Vigilance is the natural keyword to lend here because it uncouples attacking from defending, exactly the axis a wide board most wants to bend. The counter also leaves a permanent mark on whichever creature receives it, quietly tying the card to counter-matters and proliferate shells that reward bodies carrying counters. None of this is loud, and the 2/2 is deliberately unremarkable so the trigger, not the stat line, carries the value. It is a clean, low-rarity expression of a design idea that resolved a long-standing tension in white weenie: how to give a small creature a keyword without stapling that keyword permanently to a fragile body. The answer was to make the keyword transferable for a turn and the counter durable forever, so a single entrance doubles as an act of coordination.