Help find out the name of the movie!!!!!

Hey hi, please tell me the names of Wiltma, it was introduced in the late 80's and early 90's. In history (aliens in human form on earth appear, they are 4-5. They need (plutonium)) And they stand up boy, girl, boy !! I think that the artist is a comic. A distinctive feature of the aliens are two women and two men from 50 to 60 years. The film begins with the fact that these four guys are witnessing the donations (flying circus of aliens), they approached the ship, and the aliens attacked them, they got inside their bodies. Well, especially the feature (the fact that these precedents when they blow off an arm, they grow back). In the film there are moments that I remember well. 1) One woman came to have sex with the usual bangs, and the man beneath it burned))) 2) the alien was wounded in the leg, and the leg his hand raised. 3) the head of the four, going down, got hit by a train, and he again healed .....