api.bas definition, relationships, removal:

This is a part of a malicious parasite that violates user privacy and damages the compromised system. The api.bas file can be used for different purposes depending on the related parasite's type, functionality and carried payload. Although api.bas may not take any malicious actions by itself, it ensures that a parasite is working properly and therefore needs to be removed. DO NOT open, execute or edit api.bas!
The api.bas file is installed and used by Mantis (Shaban).
In some cases a presence of api.bas does not mean that your system is infected. The file may actually belong to some fully legitimate applications and therefore must stay intact. If you are in doubt, please scan the api.bas file using you regular spyware remover or antivirus program.