Nikita has a thing for shoes and likes to attack shoes that have recently been outside, especially if they're rather smelly. It's sort of funny but also not, if she's wanting to go for expensive leather shoes.
I made the mistake of leaving my Converse out one night and the next morning I found them halfway de-laced and the laces that she managed to work free she had chewed to bits.
My Oliver will do the same thing with my shoes, and occasionally with my SO's shoes.
My RB cat Lucky would fall asleep on a pair of shoes *with her head inside the shoe*. She seemed to like my dad's sneakers that he used for mowing the lawn best; second prize went to the shoes my brother wore for football. We used to tease her, "Lucky, if you keep doing that, you're going to get athlete's nose." (my dad has a chronic fungal infection due to a stint in the Army, and my brother was prone to athlete's foot in his teens).