Gularis is a Bathyosian minister, a dignitary in the Bathyosian government doubling as the leader of a terrorist group to get rid of all "air-breathers". However, his plan to turn Capital Planet into a water world was thwarted by the combined efforts of Panchax and Buzz Lightyear.
At some point in his life, Gularis became the leader of the Bathyosian Council. However, he also became the leader of a secret terrorist group known as "Bathyosians Against Air-Breathers" that sabotaged the Bathyosian mining operation in an attempt to drive air-breathers off their world. Gularis believes that the air-breathers are ravaging Bathyos through the crystal mining, and wished to strike back against them.
When Team Lightyear came to Bathyos to investigate the sabotage, Gularis had Blackfin rig an excavator to attack them, however the attempt on their lives was ultimately unsuccessful. He then tried to divert suspicion on to the innocent Panchax, head of the mining security. Eventually Buzz learned the truth, and with the help of Panchex he thwarted Gularis's plan to send a Hydro-bomb (a weapon capable of converting all the oxygen on a world to water) to Capital Planet.
Gularis was arrested and is now presumably in jail.