Mushy, as in over ripe, but still whole? If the avocado has turned color under the skin
I usually toss them, because they no longer taste good. It they are still green and not bruised, add them to your brownie mix, put in scrambled eggs, use in a smoothie, make a salad dressing. I like to brush toast with browned butter, then add avocado, leaving some chunks. It is delicious.