Add the peanut butter and soft butter to a mixing bowl.
Use the paddle attachment of the electric mixer to combine.
Add the brown sugar, white sugar, eggs, and vanilla.
Beat until completely mixed.
In a second bowl add flour, baking soda, and salt.
Whisk to blend.
Add the oats and chocolate chips.
Beat to blend all ingredients together.
Use a serving spoon to drop the oatmeal mixture over the brownie batter.
Sprinkle the Halloween sprinkles over the top.
Bake at 350 degrees for 25 minutes.
Insert a toothpick in the center to see if it is done.
When done, set on a counter for at least 30 minutes to cool.
Remove from the baking pan.