In 1932 movie
Imhotep (Boris Karloff) was a priest in the Ancient Egypt who was mummified by the Pharaoh Amenhotep III, as punishment for attempting to resurrect his love, the Princess Ankh-es-en-amon, and back from the world of the dead due to the discovery accidental of a papyrus, by a archaeologist.
He assumes a new identity, Ardath Bey, a modern Egyptian and help archaeologists to find the tomb of Ankh-es-en-amon. During the search, he comes across a woman very similar to Ankh-es-en-amon, named Helen Grosvenor. Ardath realizes that Helen is his former lover and tries to mummify it, but can't, because Helen invokes the goddess Isis, which transforms Imhotep in ashes.
In 1999 movie
Imhotep (Arnold Vosloo) was a high priest in the reign of Seti I, who was betrayed by Imhotep, who started an affair in secret with his wife, Anck-su-namun. Seti I discovers the secret and is killed by Imhotep, who tries to escape the Pharaoh's soldiers but is captured at Hamunaptra and convicted of the ritual of Hom Dai, where they cut his tongue and mummify alive, along with carnivorous scarabs beetles. Anck-su-namun, to be discovered himself, trusting that could be revived later by Imhotep, who had skills and magic formulas. If Imhotep was resurrected, he would have control over the various forces of nature, as a cloud of insects, sandstorms and invulnerability.
He was resuscitated three thousand years later, during an archaeological expedition, regenerating itself through the flesh of the archaeologists and Egyptologists. Imhotep became invulnerable, took control of the ten plagues of Egypt, but the cats were his weakness, because, according to Egyptian mythology, they were the guardians of the underworld. Finally, Imhotep was defeated with a reverse magic, by the book of Amun-Ra, who withdrew his powers and took him to the world of the dead.
In 2001 movie
In the movie "the Mummy Returns", Imhotep is resurrected again by a group of cultists, with the goal of finding the bracelet of Anubis, which he found in the Temple of the Scorpion King, which if it were defeated, the power of indestructible army of Anubis would be awarded to the victorious.
Imhotep find the bracelet, which was on the arm of Rick O'Connell's son, Alex, who is captured, with the goal of helping in the search for temple of the Scorpion King. Rick O'Connell and Imhotep fight against the Scorpion King, which is defeated by Rick, who throws Imhotep in the world of the dead.