Just looking some Mad Magazine covers [1], some amazing drawings right there, those more realistic remembered me when the Ren & Stimpy cartoon put those freeze frames with detailed and often shocking images [2], Bob Esponja also did those. Wondering if those cartoons pick some of this style from Mad Magazine.
[1] https://duckduckgo.com/?va=w&t=hk&q=mad+magazine+covers&iax=...