Bernard Dempsey used to turn into Whiptail, a creature resembling a dinosaur, after taking a serum he had created. His greatest foe was Captain Dynamo, the hero of Tower City. In time, Bernard Dempsey was diagnosed with Alzheimer's disease and currently resides in a nursing home. If the serum and the Alzheimer's have any correlation have yet to be determined.
As Whiptail, Bernard Dempsey had super strength, agility, claws and invulnerability. When transformed, he resembled a large dinosaur. He seemed unable to speak in this form as well.
A second Whiptail has been causing trouble in Tower City. It has since been revealed that this Whiptail was actually the F.L.A.G. agent, Nicole Nakamura. Thanks to her resources with F.L.A.G., she has been able to steal the serum easily. After she was defeated by Dynamo 5, she reverted to human form and was incarcerated.
Maddie Warner has stolen the serum and has injected it while facing Synergy and Chrysalis, in effect becoming the third Whiptail.