This project anti-pattern is usually describing bad or difficult people that affects the entire project and team. Usually this type of people has strong influences in project decision making.
Symptoms and Consequences
Team or project is unable to make progress become someone disagrees with their key objectives or essential processes and continually tries to change them.
One person continually raise objections, under the guise of concern, which are intractable: performance, reliability, technology market share, and so on.
Political force where the team ignores or just pleasing that person.
Heavy political environment.
Causes
Corncob person has hidden agenda, which conflicts with team's goals.
Fundamental disagreement between team members that no amount of communication can resolve.
Management does not isolate group from internal and external forces, and has inappropriately allocated roles to staff, who abuse them for their own needs.
Management failed to allocate accountability at all.