Profile, Abilities and Weaknesses description is from The Transformers: More Than Meets The Eye, comic series published by Dreamwave Comics in 2003.

BIO Scowl became a Pretender when he realized that his Autobot foes weren't scared by his appearance in the slightest. Previous to this, his alternate mode was more likely to inspire laughter than terror, which enraged the merciless and cruel Decepticon. Now that he hears his victims screaming in fear instead of chuckling, Scowl is an even more competent fighting machine. He primarily focuses on using the power of sound waves to disrupt electronic equipment and, at more powerful decibel ranges, physical objects. His fellow Decepticons wish he wouldn't spend so much time in his shell; its powerful speakers only serve to magnify Scowl's already loud, firm voice. 

WEAPONS/ABILITIES  Subject has above-average strength and intelligence, and exceptional endurance and resistance to damage. His outer Pretender shell is equipped with speakers in its mouth and can produce a variety of sonic attacks, including a wail that can rip the armor right off a Transformer's exoskeleton. The inner robot has chest-mounted speakers and ultrasonic hearing, allowing him to pinpoint the exact nature and location of even the dimmest sounds at a great distance. His sonic disruptor rifle can cause a target to either perceive damaging, over-amplified sound or total silence. Combines with fellow Pretender Monsters to form Monstructor.

WEAKNESSES  Subject's hearing is diminished slightly in outer shell. 

Bibliography of significant appearances:
The Pretender Monsters made only one appearance in the G1 continuity:
* Transformers (Marvel) #67 - In this 'alternate reality' story, Galvatron reigns supreme and has left New York City in Ruins.  Interestingly, the story is set in 2009 and depicts a deactivated Rodimus Prime hung between the Twin Towers of the World Trade Center.  
* In later years the team was featured in GIJoe / Transformers Crossover series published by Devils' Due comics.
* The team was also featured in the IDW-verse as the lone combiner.  Apparently, in their view, combiners are an unheard of concept until Monstructor is developed by Jhiaxus...

Other Appearances: