Complex sentence: Just before Mutant kills Skipper by dropping from the ceiling of his private office, Libby appears in the doorway and defects Mutant with a yellow toy gun called Molecule-Melter.
Split into simpler sentences: Just before Mutant kills Skipper by dropping from the ceiling of his private office, Libby appears in the doorway. Libby defects Mutant with a yellow toy gun called Molecule-Melter.