Tyson Dense is a villainous bat. Perpetually angry and a very bad loser, Dense one day flipped after trees near his house decided to shed their leaves all over his car. Keen to sort nature out, Dense produced a vehicle that could chop trees down with all sorts of sharp peripherals and entered the machine into Enviro-Fete '98, an exhibition created to discover inventions that help the environment. Having completely missed the point, the Enviro-Fete judges informed Dense that he had not won. Watching Tekno the Canary win first prize for her solar-powered Hover Scooter, Dense took offense to the snub, got in his machine and attempted to kill Tekno and Amy Rose. He pursued them into the Emerald Hill Zone forest, chopping aside all trees in a mad rush to catch the girls and taunted Amy when she pulled out her crossbow, stating his machine had no weak spots. Unfortunately for him, it did. The subsequent explosion sent Dense flying into Roger Bodge's self-warming bath.
Dense returned much later as a member of the League of Super-Evil Villains. His inventing prowess had attracted the attention of Grand Chief Whip who required his services when breaking into the Metropolis Zone Central Bank. Things started badly when he suffered dizziness from The Leaf's bad landing and soon felt ill, believing one of his polluto-bombs had fallen out somewhere. Inside, things got worse when his mechanical Boxing Glove contraption failed to penetrate the vault's door. Not yet beaten, Dense produced an oil gun to melt the door. The Leaf knocked it out of his hands, realising that contact with hot oil on a frozen vault door (thanks to Windy Wallis) would cause an explosion. Bob the Plax clearly wasn't listening, using Dense's gun and destroying the whole bank. Dense was soon arrested with the arrival of Sonic the Hedgehog and the police.
Dense returned with the League under the new leadership of Doctor Genius. At one of their first meetings, Dense appeared to be bored and suggested that they lie low, hiding from the threat of S.P.E.A.R..
- Despite having wings, Dense was never seen to fly (except when he was blasted away by an explosion).
- His appearance in the print run was rather bestial and demonic. In Sonic the Comic Online, he looks more cartoonish.