Before entering the superhero business full bore in the mid-60's, Hanna-Barbera experimented first with funny animal heroes. Quick Draw McGraw, for example, was given a masked alter-ego, El Kabong, a parody of Zorro, but it wasn't much in terms of maintaining a secret identity. File it under "transparent".
In 1962, as part of the syndicated Hanna Barbera New Cartoon Series, Touche Turtle sallied forth to combat evildoers. The setting could be medevial times or contemporary, but the only constants were Touche (Bill Thompson, the voice of Droopy) and his canine assistant, Dum Dum (Alan Reed, The Flintstones).
My first exposure to Touche was in the early days of cable and reruns aired weekdays on WSBK. However, it was originally intended as a weekly series, with a new episode each week for 52 consecutive weeks. Unfortunately, the series didn't click as well as it could have, and was cancelled after 1 season.
Cartoonsintros uploaded the open:
Touche would return as part of Yogi's Gang, but hasn't been seen since.