In MANET applications, a common pattern is to maintain and query time-varying collections of remote objects. Traditional approaches require programmers to manually track the connectivity state of these remote objects and adding or removing them from local collections on a per-object basis. Queries over these collections have to be manually recomputed whenever the collection or its elements change.The code for maintaining these ad-hoc collections is scattered across the application code and leads to bugs hindering the application development process. In this paper, we propose an object-oriented abstraction called ambient clouds: a collection of objects whose contents are implicitly updated when changes occur. Ambient clouds can be queried and composed using reactive standard query operators. We show how ambient clouds ease the development of a collaborative peer-to-peer drawing application.