If you search what is Sprunki, the short answer is yes — Sprunki is originally a fan-made mod of Incredibox.
But that answer alone doesn’t tell the whole story.
What Sprunki actually is
Sprunki started as a community-created modification built on top of Incredibox’s core idea: dragging icons onto characters to create layered music.
The gameplay is almost identical:
You assign sounds (beats, vocals, effects) to characters
Each character loops a sound
Everything syncs automatically into a track