Professor "Tobber" Homlomium (probable first name English Spark, a member of the Queen's Society, and a researcher on multidimensional space, with particular interest in the possibility that higher dimensions are by powerful beings who might object to the manipulation of time, specifically at Mechanicsburg. So he derived purely from theory something the reader (along with Gil and Higgs and the Castle) has first-hand. This disturbing area of study, along with (evidently) his personality, led to him being unpopular with his fellow Society members.) was an
At some point during his research, he and his nose parted company, and he installed a metallic replacement.
The Foglios, with their ongoing relaxed attitude towards spelling, sometimes give his last name as Homnomium.
His current lab assistant is the humanoid amphibian Trogulus.
Around the time Agatha arrives at the undersea dome housing the Society, Homlomium goes missing. A plumbing disruption leads to the discovery of the aforementioned jammed in a drain, leading to the assumption that its owner got stuffed in there as well. The prevailing theory is that he was killed to prevent him from meeting Agatha, a hypothesis which is backed up by some unknown individual murderously breaking into his lab and all of his blackboard equations. However, another(?) anonymous individual (perhaps Trogulus) begins distributing Tobber's book-bound research notes to various Society members, including Agatha. Someone also murders the two doctors conducting Tobber's autopsy, leading to the by Krosp that the pulped organic material (supposedly) recovered along with the nose is not human. Additionally, Krosp and then Dr. Dim/Vapnoople confirm that that Tobber (or, in Vapnoople's words, "young Tobias") has met with the latter man since he arrived at the dome with Krosp. Hearing this, Agatha and Wooster go chasing after Tobber. However, Da Boyz and Zeetha get there first, and drag who they think is Homlomium into view, still alive and kicking.
But this Tobber-looking person turns out to actually be Trogulus in disguise. Hethat yes, Homlomium really did get stuffed down the drain, and that he, Trogulus, murdered the doctors (but only the doctors) and replaced Tobber's remains with ground beef, so that their enemies will believe he's still alive.
Said enemies, the "Grey Hoods" as Trogulus informally refers to them, are mysterious even to him, beyond wanting to use Tobber's research for their own nefarious ends. And it is finally by the group itself, that they were the ones who killed him, though they are indeed fooled by Trogulus's impersonation into thinking Tobber is still alive and working with Agatha and Co.