Answer:
I think I've figured it out. Bathos is used for comical effect. For example;
If we look at this example from the novel Pride and Prejudice, written by Jane Austen
"When Lydia went away she promised to write very often and very minutely to her mother and Kitty; but her letters were always long expected, and always very short."
Austen builds up the sentence saying that Lydia had said that she would write alot to her mother and sister, they would always wait for them but in the end the letters were always short. That in theory is the comical effect. They would wait for the letters everytime but the letters were always short, where you would expect them to be longer if they were long expected.
P.S. That's what i Think it is. Doing an essay on Pride and Prejdice for English GCSE so that's how i figured it out.
actually.. Bathos isn't always used for comical effect although sometimes it can. Bathos is an exaggeration of pathos. For example someone trying too hard to passionate about something.
so sometimes satirical pieces contain bathos but bathos is not always funny on purpose.