He was a Lost Number - a Zoanoid who, because of an unforeseen flaw in his processing, develops some unique quality and cannot be reproduced. All Lost Numbers are one of a kind. Some die, some are hideously malformed, some are functional Zoanoids with as their only flaw that they can't be replicated. And some have unique abilities that make them useful as test subjects or, in the case of the Lost Number Commandos, warriors.
Of the three special commandos, Somlum was the most like a normal Zoanoid; he resembled a semi-humanoid lizard with a long tail, armored skin, razor-sharp claws and a row of spines down his back. Somlum`s strong legs allow him to excel in jumping to great heights. He also possessed the ability to secrete and spew a unique adhesive - not an ordinary glue, but a molecular bonding agent which would actually merge with any object it touched and could not be removed. Indeed, the Guyver did manage to rip himself free but at the cost of some grievous injuries; nevertheless, he did free himself and killed Somlum immediately after.
His death, and that of Dyme mere moments later, would haunt their comrade Aptom for years to come, and inspire a vendetta which would, ironically, turn him into one of the Guyver's strongest allies... and Chronos' deadliest enemies.