It is a harmless nonmemory resident parasitic virus. It searches for .COM files in the current directory, then writes itself to the end of the file. The virus writes CALL_Virus instruction to the middle of the file. To do that it scans the file for the B4h ?? CDh 21h bytes (MOV AH,?? ; INT 21h call) and replaces these bytes with CALL_Virus code. Before return to the host program the virus restores these bytes.
The virus does not manifest itself in any way. It contains the text strings:
*.com [Simbioz.Inside]
