Zealous zarches are giant long legged creatures, encounterd by Spaceman Spiff, in a Sunday strip. In reality, they are Calvin's parents that look for him.
In the strip, Space man spiff (Calvin) is being chased by two of them (Calvins Mum and Dad) on the planet Plootarg (outside in the snow) After disscovering that the planets soft granular (the snow) makes him easy to track (because he leaves foot prints) he runs backwards, so his tracks so him going the opposite direction;
The strip ends with Calvin hiding from his parents (up a tree) with his Mam saying: Calvin! it's time to come in! and his Dad saying: We know he went this way. We'll find him.