Boing sound effect

One taut twang wobbling fast and settling. Short enough to land on a frame, which makes it punctuation rather than an event.

A slack spring oscillating slowly. The longer settle reads as comic exhaustion where the taut version reads as impact.

A tone climbing as the spring is pulled. It reads as tension building, so it sets up a release rather than delivering one.

Three boings getting smaller and quicker. The diminishing pattern is exactly how a real bounce decays, and it reads as physics.

A heavy low twang from a thick spring. It implies weight, so it suits something large landing rather than something light.

The twang followed by a dull landing. The thud is what resolves it, so the gag ends rather than trailing off.