Complex sentence: In 1986, Playskool released a number of Glo Worm toy lines that glowed but were made of hard plastic these were so successful that American fast food chain Wendys in 1989 also released a series of 12 hard plastic Glo Worms to advertise their chain.
Split into simpler sentences: In 1986, Playskool released a number of Glo Worm toy lines that glowed but were made of hard plastic. These were so successful that American fast food chain Wendys in 1989 also released a series of 12 hard plastic Glo Worms to advertise their chain.