We present TilePoP, a new type of pneumatically-actuated interface deployed as floor tiles which dynamically pop up by inflating into large shapes constructing proxy objects for whole-body interactions in Virtual Reality. TilePoP consists of a 2D array of stacked cube-shaped airbags designed with spe-cific folding structures, enabling each airbag to be inflated into a physical proxy and then deflated down back to its original tile shape when not in use. TilePoP is capable of providing haptic feedback for the whole body and can even support human body weight. Thus, it allows new interaction possibilities in VR. Herein, the design and implementation of TilePoP are described in detail along with demonstrations of its applications and the results of a preliminary user evaluation conducted to understand the users' experience with TilePoP.