msem-instigator

Improve {1} ({1}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
At the beginning of combat on your turn, target creature you control with mana value 3 or less can't be blocked this turn. If Streetwise Investigator has two or more counters on it, that creature gains vigilance until end of turn.