Time-stretching
Changing how long a sound lasts without dragging its pitch along — the trick a tape machine at the wrong speed could never pull off.
Play tape faster and it gets both shorter and higher; time and pitch are welded together. To pry them apart, algorithms chop audio into short grains and overlap them more or less densely (overlap-add, WSOLA), or rework the signal in the frequency domain with a phase vocoder, described by Flanagan and Golden at Bell Labs in 1966. Pitch shifting is the same thing run backwards: stretch the time, then change the sample rate.
Ableton Live made it a way of working in 2001, with every loop following the song's tempo automatically. The artefacts are well known: smeared drum hits, a metallic "phasiness", and vocals that sound as if they were recorded inside a barrel. Modern algorithms detect transients and protect them, but an eightfold stretch still sounds exactly like what it is.