ok heres cujo for space au. theres not really a scale but think jack russell terrier for the small form and like 7-8 ft (ish) for the large form (there will be team lineups at some point so theres a better size comparison)
his design concept was thought out as 'LIKE a dog... but mostly just an alien' so i took that and went 'bear-lizard'
cujo's species is a subset of anubi on planet stellegarra that can shift sizes; the small size is fully quadrupedal but when they shift to larger size they can walk on two legs for short times (think bears walking on hind legs).
the anubi language is barky and growly as youd expect but the anubi (and everyone else) have little translators; the resulting effect is much like what can be seen from doug and the other dogs in the movie 'up' by pixar haha