Ages ago, I read a sci-fi book about an alien telepath, very human in shape, who can suck knowledge, experiences, and personalities out from the brain of humans, killing them in the process. He tries to climb up the 'social ladder', getting a high-profile fiancee, using the skills he 'learned' from being a playboy, and being killed by the girl's cats at the end.
According to the back cover plot summary for a standalone printing of the story provided at goodreads.com:
The space ship came plummeting out of the sky---a soundless, streaking, purple glow, moving faster and faster until it ripped at the trees, crashed through them and struck sickeningly against a hill. Momentarily it flared brightly, then went out.
It was not long after that the murders began---strange, inexplicable deaths, all victims found with their heads crushed as if their skulls had exploded outward.
The trail of victims led from Arkansas to Tennessee, to Kentucky, Illinois and Michigan---sixteen unrelated people who had only one thing in common: All of their brains were withered, as if sucked dry of their contents...
And somewhere wandered an evil stranger from another planet, his personality expanding, his brain power increasing, preparing for the inevitable encounter that could make him master of the world!