The katarn was a type of vicious lizard that lived on Kashyyyk. Wookiees believed katarns had a mystical connection to the land, considered them sacred... and killed them by the hundreds in ritual hunts. Huh. Wookiee logic, I guess.
The family of Kyle Katarn was named after the katarn, but the katarns are sick of people bringing him up in conversation and will probably kill you if you ask.