An acquisition whose primary purpose is hiring a startup's team, usually structured as a small upfront price for the company plus large retention grants and signing bonuses for the individual engineers.
Facebook paid an estimated $47.5M for FriendFeed in 2009, and the acquired team, including Bret Taylor and Paul Buchheit, drove the next decade of Facebook's product roadmap. The FriendFeed product itself was wound down within months. The deal became Silicon Valley's reference example for the engineer-first acquisition.