I wasn’t raised as a life-form of limited imagination. But truthfully, on my home planet, no one could have imagined that there is something that walks around on two legs swinging its two arms. The idea of it must have been tossed around at some point, but we would be hard pressed to believe that bipedalism was really possible and that there really is a whole group of life-forms out there somewhere living on two legs.
I think humans would share this sentiment about your planets life-forms, tripedal-ism (if that's even a word) isn't common to us and if we were forced to be tripedal… we'd all look like toddlers walking lol