Silk is the high-octane bug juice that keeps Hornet alive in Hollow Knight: Silksong. She burns it to heal, and she also burns it to pull off some seriously flashy offensive moves. The usual way to refill the meter is to land hits, which is great for aggressive players who treat every room like a boxing ring. But for anyone who prefers a little passive income, the three Silk Hearts are the real prize. These things quietly restore a portion of the Silk meter without asking for much in return.