PSA: The "blurring" effect in One Punch Man S2 is NOT J.C. Staff's doing : r/anime
The Art of the Smear: A Secret Animation Trick - Ceros Inspire
Animation Techniques: The Smear - IdeaRocket
How To Animate with Smear Frames! - YouTube
Motion blur, smears, and multiples - Moho Forum
amid on X: "Motion blur is artistically lazy (l.) Respect each frame and design it (r.) https://t.co/MwRRr0Opm4" / X
So the "motion blur" from the Lego Movie post two days ago is actually an animation technique known as a "smear." Here's some more info and examples from various movies. : r/movies