80’s 90’s movie lost

I am currently trying to hunt down a movie title that I saw a long time ago and I can’t remember for the life of me what the title was I tried researching on Google and got nowhere here’s what I remember there was a alien ship crash on earth and these rock looking creatures came out  looked kinda like “the thing” from fantastic 4  and they are trying to repair their spaceship but they need to blend in with us So they are stealing our DNA so that they can look human and keep their human form longer so that they can repair their spaceship one is a female and the other is a male