Probably one of the most popular re-incarnations of the Transformers action figures came with the Beast Wars story line, released between 1995 and 1999, which had robots that were capable of transforming into animals.
As with the original G1 Transformer figures an animated TV series was also introduced to support the line.
In the Beast Wars the Transformers are stranded back in the past - on Earth, when the Earth was full of Energon, a substance that causes the Transformers to overload their circuits.
In order to prevent this happening they assume the form of animals. The Autobots descendants, the Maximals, and the Decepticons descendants, the Predacons battle for superiority.
Optimus Prime, the Maximals leader, took the form of a gorilla and Megatron took the form of a tyrannosaurus rex, eventually evolving into a terrifying dragon.
Blackarachnia, the first mass-produced female Transformer, was also introduced in 1996.
In 1998 the Fuzors and Transmetals figures were introduced to the Beast Wars line.
The Fuzors were robots whose beast modes were a combination of two different animals and the Transmetals are Transformers that developed metal superstructures after an energy wave hit the Earth.
The Transformers Beast Wars figures had excellent sculpting with great attention to detail and became one of the most successful lines, spanning a period of almost 6 years.