Complex sentence: Jerry then runs away as Tom shoots a stream of balls at him, which chase Jerry in and out of various pockets on their own accord, until Jerry jumps on Tom and opens his mouth, causing Tom to swallow all seven balls.
Split into simpler sentences: Jerry then runs away as Tom shoots a stream of balls at him, which chase Jerry in and out of various pockets. The balls then chase Jerry on their own accord, but Jerry jumps on Tom and opens his mouth, causing Tom to swallow all seven balls.