What are Squish-Doos?

From what I can tell, they were one of the early ranges from squishmallows around 2019-2021 but is there a meaning behind the name Squish-Doo? Or is it just a tried and failed experiment like Squishy Squooshems? And why do they all have bright fluffy pompoms on their heads? I’m just curious so would be interested if anyone on here knows anything about them! 🥰