You're best to pre-cook mushrooms and bacon first or else the juice / fat they release will make the pizza soggy - just a tiny splash of oil in a frying pan over a medium heat and cook until they don't release any more liquid, then they'll be ready to use on your pizza. Don't worry about the mushrooms overcooking on the pizza. They aren't technically vegetables so the normal rules don't apply! Cook them until they're brown. Just undercook the bacon slightly though. If using spinach for instance to make a beautiful green eye, wilt it first in a pan, pat it dry then add to the pizza after it comes out of the oven so it doesn't overcook or make your pizza wet. I like to soften my pepper strips in the frying pan to make them flexible to shape for this too

I like to spread garlic butter on top of the half cooked dough then on top of that tomato paste, pesto and grated cheese / cheese substitute. Add circles of mozzarella style cheese to make the whites of the 'eyes'

https://cookpad.wasmer.app/us/recipes/357071-vickys-savoury-compound-butters-gluten-dairy-egg-soy-free

Now add your 'iris' on top of the cheese slices. I've used sliced pepperoni but you can use anything you like. Chopped green pepper, spinach, sweetcorn...

Add the olives or mushrooms for the 'pupil'

Now bake for 12 - 15 minutes or until the toppings are all cooked through and the base is crisp

If making one big eyeball, serve as a whole pizza then at the table use a fork to distribute the piled topping evenly over the whole surface before slicing in front of everyone

And it doesn't need to be scary for the kiddies either