Bottom-up (maybe OP less so) for-fun collaborative (re)animations like this are most commonly called Multi-Animator Projects[1], at least presently in certain parts of the internet. They're found everywhere else you'd expect under different names. Some of the earliest web-originals are still on newgrounds and niconicodouga, but aren't easy to find.
Another name is the pattern of "/a/ draws", "/v/ draws", "r/anime draws", etc, from 4chan. Those would be the most similar ones to OP in terms of mspaint-like quality and quantity of penises[2].
You must be unaware of the phenomenon of /int/ :DDDD
First found on the German site Krautchan, you could hardly describe a forum so inclusive as one dedicated to cultural exchange where anyone may flame in any thread in any language. The concept spread quickly among the chans. And so the users of the /int/ boards became worldwide pollinators of memes, the DNA of the soul.
That optimistic era is passed, however /int/ remains the sixth most active board of 4chan.
Shiba, Amezou, Nishimura, and Kosugi; Kyanka and Poole and Degrippo; the nanashi, the goons, and anons: all pawns in Hideaki Anno's master plan, set in motion by the prophetic creation of moot's waifu of Axis-American descent.
Another name is the pattern of "/a/ draws", "/v/ draws", "r/anime draws", etc, from 4chan. Those would be the most similar ones to OP in terms of mspaint-like quality and quantity of penises[2].
[1] overview and a decent directory: https://fanlore.org/wiki/Multi_Animator_Project
[2] archived results page with no personalization: https://archive.is/80U5G