Bio-Con (short for Bio-Constrictor) is a supporting antagonist in the Max Steel franchise. Dr. Klimo, once a highly respected scientist in the field of bio-experimentation, was involved in a tragic accident that mutated him into a snake-human hybrid with the ability to turn himself or his limbs into autonomous serpent appendages. As with most cartoon villains, his one goal is to make Max Steel pay for the accident, and wants nothing less than Steel's destruction, even if that means teaming up with those he views as weaker beings.
Rene Auberjonois lent his voice to Bio-Con in the 2000 series. As cliche as it is, the quiet, raspy voice with the emphasized s's is perfect for the character and Rene pulls it off without being too over-the-top.
The DTV movie Endangered Species saw the voice cast go to the Vancouver area, and what better voice actor to voice a sssssslippery and raspy-voiced reptile-villain than Ssssssscott McNeil? Scott's take is more more ssssssslithery and raspy than Rene's, so he's a natural fit.
While both are good, I'm going with Scott on this one.