Tracking down five lost flea locations for Fleamaster Mooshka in Hollow Knight: Silksong might remind you of rescuing the grubs in the original game (if you played it). Mooshka's fleas have flown off across the kingdom and are now trapped in all sorts of tricky to reach spots.
You can undertake The Lost Fleas quest at the flea caravan in The Marrow near the start of the game to rescue them. This sees you finding five fleas in the lower reaches of Pharloom, though as you progress higher towards The Citadel, you'll encounter even more in need of help.
