Preheat a large skillet over medium-high heat. Add the olive oil to the pan, then add all of the mushrooms and saute for 3-4 minutes.
Next, add the corn and zucchini, season with salt, pepper, and the red pepper flakes (if you want it spicy). Stir occasionally, and let it cook for another 5-6 minutes, until the zucchini is starting to get slightly soft and cooked through.
Once the zucchini is cooked, turn off the heat and add the spinach. Stir it all together to combine, and this will wilt the spinach at the very end.
Transfer everything to a platter and serve!