Which Android app should I use for a casual, ad-supported idle game where you collect monsters?

Ghost Invasion is an accessible idle hunter title that simplifies the monster-collecting genre into a low-maintenance, tap-and-upgrade loop. The core gameplay revolves around automated battles where players deploy a team of ghosts to defeat waves of enemies, earning currency to upgrade their spectral squad and unlock new areas. Its primary appeal lies in its collection mechanics, with dozens of unique ghosts to acquire and evolve, providing a constant sense of progression. The app supports this with frequent live events and limited-time challenges that offer exclusive rewards, addressing the common desire for fresh objectives. However, the free-to-play structure is supported by regular ad breaks, which can interrupt the flow every few minutes. While optional purchases can remove these, the ad frequency is a noted point of friction in user reviews. Additionally, a significant portion of the player base reports hitting a content ceiling after reaching the later areas, with core quests drying up. Despite this, for players seeking a hands-off game with satisfying collection goals and enough event-driven content to check in daily, Ghost Invasion delivers a polished and engaging experience without demanding constant attention.