Spontanzauber
Kräftigung 4. (Lege vier +1/+1-Marken auf eine Kreatur mit der geringsten Widerstandskraft unter den Kreaturen, die du kontrollierst.)
You determine which creature to put counters on as the spell or ability that instructs you to bolster resolves. That could be the creature with the bolster ability, if it’s still under your control and has the least toughness.