I was also a victim of this. At my first engineering job, I came up with a novel way to handle project estimation for a very large company, using a combination of basic statistical techniques (hierarchical linear regression, markov chains). It replaced an existing terrible model by the resident PhD in statistics, which was doing a very simple 2 degree fitted curve.

Anyways, this person seemed to really dislike our team and what we had accomplished, and was constantly trying to road block us for a long time. Then out of the blue, he asked us to come and explain it to him. I thought he was reconciling, and we showed him all the details and spent a while so he could understand. We provided him the implementation as well. Then 3-4 weeks later, he quit to go work at Apple. It seemed like he'd stolen our work to improve his career.