Smilodon

No evidence for real fur(any fur impressions and the sort are just grasses)- add scales, scutes, and spikes, all the cool kids are doing it

Smilodon was too large to have fur, and fur is a crap insulator compared to, say, feathers, that allow things to stay both warm -and- cool when needed, it would've overheated with any assortment of fur. This large beast would've simply had naked skin and scales.

No reason to add that nasty extra skin and muscle either.

Calling it a 'cat' would be degrading, especially if you add fur. No one would believe this thing would look like a cute little kitty, so wimpy.