  App markets have evolved into highly competitive and dynamic environments for
developers. While the traditional app life cycle involves incremental updates
for feature enhancements and issue resolution, some apps deviate from this norm
by undergoing significant transformations in their use cases or market
positioning. We define this previously unstudied phenomenon as 'app
metamorphosis'. In this paper, we propose a novel and efficient multi-modal
search methodology to identify apps undergoing metamorphosis and apply it to
analyse two snapshots of the Google Play Store taken five years apart. Our
methodology uncovers various metamorphosis scenarios, including re-births,
re-branding, re-purposing, and others, enabling comprehensive characterisation.
Although these transformations may register as successful for app developers
based on our defined success score metric (e.g., re-branded apps performing
approximately 11.3% better than an average top app), we shed light on the
concealed security and privacy risks that lurk within, potentially impacting
even tech-savvy end-users.
