Complex sentence: He fancies himself to be a great and powerful magician, but has absolutely no powers and often resorts to using cheesy special effects (such as the old' hot water and dry ice fog bit) to impress others.
Split into simpler sentences: He fancies himself to be a great and powerful magician. But has absolutely no powers and often resorts to using cheesy special effects (such as the old' hot water and dry ice fog bit) to impress others.