"A bison as an astronaut, tone mapped, shiny, intricate, cinematic lighting, highly detailed, digital painting, artstation, concept art, smooth, sharp focus, illustration, art by terry moore and greg rutkowski and alphonse mucha"
I've found that sometimes you need a lot of attempts to get good results. Here's a run I just did, I'd say the top left result is OK, the bottom 2 are wrong/misinterpretations, and the top right result is fantastic: https://i.imgur.com/l8BsWvI.png
This is my bison astronaut:
https://i.imgur.com/ohIuG6F.png
The prompt was:
"A bison as an astronaut, tone mapped, shiny, intricate, cinematic lighting, highly detailed, digital painting, artstation, concept art, smooth, sharp focus, illustration, art by terry moore and greg rutkowski and alphonse mucha"