Pafish is a demo tool that performs some anti(debugger/VM/sandbox) tricks. Most of them are often used by malware to avoid debugging and dynamic analysis.
The project is open source, you can read the code of all anti-analysis checks. You can also [download](https://github.com/a0rtega/pafish/raw/master/pafish.exe) the compiled executable (or compile it by yourself) and reverse engineer it, which is quite recommended.
The objective of this project is to collect usual tricks seen in malware samples. This allows us to study them, and test if our analysis environments are properly implemented.