Tunnelling
Also said as Bullet through paper, Clipping through walls
A fast object moves so far in one physics step that it starts on one side of a wall and ends on the other, and the game never sees them touch. Collision was only checked at the two ends.
It is why things fall through floors when the frame rate dips. It only happens with fast or small things, so it survives testing and then shows up on someone's slow laptop.
Say it
“Bullets move 25 px a step and the wall is 12 thick, so they can tunnel. Use a swept test, a raycast from the old position to the new, for anything that fast.”
Where you’ve seen it
Super Mario 64 moves Mario in four quarter steps each frame, checking for surfaces at every one: sub-stepping, the simplest fix for this problem.
Not to be confused with clipping
Clipping is any visible overlap, often harmless, such as a sword through a cape. Tunnelling is a real collision being missed entirely.