Mimicry Marcus (Progenitor Virus)
A slew of countless leeches that takes the form of the late Professor James Marcus*. When threatened, the leeches abandon their illusion, reform, and prepare for attack (while they still maintain a vague humanoid form, all vestiges of Professor Marcus disappear completely). They attack by elongating what would be the arm, lashing it out like a whip.
*Professor James Marcus:
The first head of the Umbrella Management Training Facility.
Grouping together to mimic another creature is extraordinary behavior for lowly worms such as leeches to display. This behavior is a result not only of the accelerated evolution of each individual leech due to the Progenitor virus, but also of the fact that the leeches have developed a way to share and process information with each other in the same way that computers can perform parallel processing. This phenomenon would not have been possible without the Progenitor virus, a marvel even Professor Marcus himself would have been unable to foresee, and it is proof that the Progenitor and T-Virus's mutational and evolutionary abilities are beyond current human understanding.