This hit me while I was running in the freezing cold.
This is Mufflehead, a no-nonsense muffler. There’s no bulk around the neck, down your back or on your chest. Folded, it serves as a headband & turtleneck, unfolded, a full muffler & almost-hat. Worked in one piece in ribbing, it fits just about every head & instructions are given for various weights of yarn. Warning – this one’s very adictive – you may end up making dozens!

(Also fits 15 - 20 lb pooches … includes suggestions for sizing)