The standard way for a BIONICLE character to go, if they happen not to play a very very crucial role, probably to show off how Darker and Edgier the story has become. Reached the status of a Running Gag for the fandom.
The first notable example is Botar, a mysterious and thoroughly loyal servant of justice, also a jailer with the power to teleport, who already appeared in a scene or two — got his organs crushed just so that the main characters could escape, only to be replaced by another member of his species shortly thereafter.
Carapar, one of the main antagonists for a whole year-long arc, former warlord, who went on to become part of a rag-tag misfit group sent on a mission by the good guys — zapped to dust to show off the otherworldliness of an Eldritch Abomination they chanced upon, never to impact the plot.
Ancient's fate could well be the worst example of this in the franchise's run. Just read his entry over here.
Guardian, a Narrative Filigree kinda guy who for the first time got a spotlight, grouping together with the mainest of all characters — within seconds, the baddie crushed him purely For the Evulz.
Nocturn's death happened off-screen, and we only learned about it from a casual comment made by the Big Bad in his book, which didn't even specify the details beyond that he was killed while trying to escape the Pit. He also noted that Gadunka had been gulped up by a shark.
When the Masters of the Universe Classics "Snake Man-At-Arms" figure was released, his bio told that he was killed by Clamp Champ. This felt as the trope as it was just being alluded in a bio. When the scene was finally shown in a minicomic, the comic space was so misused with an excess of double-page spreads that the relevant scene was limited to three panels of the few pages left, which leaves the scene so truncated that it still fits the trope.