Hanamaru Youchien reminds us about the visual trope of head-riding, where a cute blob rides someone's head. By necessity, for the gag to click, the blob has to be no larger than 2 heads. Which is perhaps why ostensible "children" in the Hanamaru are so small. Funnily, I do not hear whailing about Hanamaru's art like the one the big heads of Manabi produced!

The head-riding can be found in managa too. Here's Chihaya being ridden by her own puchi in Puchi-ma(ster):

I think in anime Potemayo brought the blob to the forefront, and Hanamaru followed upon that, but surely the tradition should originate further back than that.