Inhibitor spike

Also known by the euphemism mouth flowers, inhibitor spikes are horrible Decepticon restraining devices. They are screwed directly to the roof of the mouth, sending a telescopic metal spike through the subject's brain if they attempt to remove it or transform.

Fiction

2005 IDW continuity

Early in the war, Skids was captured by a Decepticon hygiene team and incarcerated in Grindcore. There, he was taken to the "fitting room" where Flywheels gleefully introduced him to the "mouth flower". When Rev-Tone inquired what the Decepticons did if a Transformer didn't have a mouth, Stalker was only too happy to demonstrate how they improvised using a large, bladed weapon.

Once in his cell, Skids removed Quark's inhibitor spike using his outlier skills; having seen them being constructed, he was able to easily take them apart again. Speak, Memory: Part 1