Flattop persuaded his fellow Autobot cadets Tailgate and Subsea to undergo a rite of passage in Cybertron's treacherous Underworld. Once there, they found it populated by violent, malformed mutants. Paralyzed by fear and guilt, Flattop was helpless to save Subsea from a grisly death, and he himself was soon incinerated by Smeltdown. Underworld!