The ornamental design for a collapsiblebabybottle, as shown and described
.
FIG. 1 is a perspective view of a collapsible baby bottle, showing my new
design; the broken line showing is for illustrative purposes only and
forms no part of the claimed design;
FIG. 2 is a front elevational view of the collapsible baby bottle, the
rear, left and right elevational views are mirror image of the front view;