If its firm when raw you can grate/ shred

and use it in bars…. Use a zucchini recipe.
Or do that and use it in spaghetti sauce, taco meat, if the pieces are small they will kind disappear into the sauce/meat mixture.

If its too soft for that you could cook it and mash it up, hide it in mashed cauliflower or mashed potatoes.
Use that mashed up squash to thicken a soup or stew.
Or use it with banana in a banana bread or muffin recipe.