Origin
Nothing is known about Bigmouth. At some point, it came into the possession of, or was created by, Judge Gallows.
Creation
Bigmouth was created by Dave Wood and Curt Swan. It made its first appearance in The Unexpected #113.
Character Evolution
Silver Age
In the Silver Age, and continuing through the Bronze Age, Bigmouth showed no evidence of sentience. It appeared to be an ordinary gavel, with the whimsical addition of a carved human skull in between the heads.
Modern Age
In the Modern Age, Bigmouth became sentient. No further information was given.
Major Story Arcs
Judge Gallows
Bigmouth is wielded by Judge Gallows during his various trials. It has little input in the proceedings, and rarely even gives evidence as to its sentience.
Powers and Abilities
Bigmouth is a sentient skull which has been crafted into a gavel. Its actual powers are unknown.