Monster Lair is a free Android application developed by Robert Morawa that helps Pathfinder Second Edition players to create and export their encounters. The app includes core features such as encounter calculator, random encounter generation, random treasure generation, and the ability to add custom monsters to encounters. Moreover, it offers a comprehensive list of monsters, hazards, and treasure from all sources with filters for traits, rarity, etc. The app provides the option to save encounters as PDF or print them for use at the table. Additionally, it is Dark mode ready. It is important to note that the developer has decided not to maintain the app beyond the current state and content, which includes everything until Bestiary 3.

In terms of usability, the app is easy to navigate and the interface is user-friendly with a clean layout. The encounter builder is straightforward and allows for customizations with the option to add notes. The random encounter generation feature provides a quick way to generate encounters with the option to select templates. The app's integration with Archive of Nethys is a useful feature that allows for quick access to monster information. Overall, Monster Lair is a helpful tool for Pathfinder Second Edition players looking for a comprehensive encounter builder.