When a signal asks for more level than the system can represent, the peaks simply stop, sheared flat at the ceiling. On a waveform the rounded tops become plateaus; to the ear, clean material grows a hard, buzzy edge as the flattening manufactures harmonics that were never played.
Digital clipping at 0 dBFS is the harshest form, an instant transition from perfect to broken with nothing gradual about it. Analog circuits and tape saturate instead, compressing peaks progressively, which is why “analog warmth” and “digital harshness” describe real physics and why plugins simulate the former to avoid the latter. Producers do use clipping on purpose, shaving drum transients to trade peak level for loudness, and an entire loudness-war aesthetic was built on it.
The visual analog is literal: a meter or a picture driven past its range flattens the same way, detail lost at the top. Photism’s auto-exposure exists for exactly this reason, riding the visual gain so loud sections stay structured instead of blowing out to white.