It sounds like a misremembering of the previously-mentioned Quatermass and the Pit (which in the US was released as Five Million Years to Earth, a title which seems chosen to cause confusion with Ray Harryhausen’s \Twenty Million Miles to Earth). It’s an excellent and generally-overlooked science fiction gem, based on a script by Nigel Kneale.
But in the film, the “grasshopper” things are long dead. It’s their automatic computer system – which is built into the ship – which is controlling the minds of first one, then several people (Kneale’s Quatermass scripts always seem to ultimately involve aliens “taking over” people somehow). Worth the watching, if you forgive the occasional stupidity.
There are [p]plenty* of bad Giant Grasshopper flicks. Watch Killers from Space. Or another British import that has some of the elements quoted in the OP – The Strange World of Planet X, released in the US as The Cosmic Monsters. as i’ve said before, it’s hard for me to believe that Stephen King didn’t rip off his story “The Fog” from this little flick. It stars Forrest Tucker, who played the tough American hero in quite a few 1950s British SF movies.
- Quatermass an the Pit was originally a six(?) part British TV serial, which is itself available on tape and DVD, and worth looking up in its own right.