Gul Spumco was a Cardassian officer in the 2350s.
In 2357, he was kidnapped by the Bajoran underground. Surmak Ren was convicted for terrorist activity related to this incident the same year and sent to the internment camp on Velos VII. This information was in Dr. Surmak's file in the Bajoran Archival Records as of 2369. (DS9: "Babel")
This character was only mentioned in writing.
"Spumco," or Spümcø rather, is the name of the animation studio responsible for the the cartoon Ren and Stimpy. This was the second Ren and Stimpy reference made in this episode, following the reference to Surmak "Ren".