These are dangerous memory resident encrypted parasitic viruses. They hook INT 16h, 1Ch, 21h and write themselves to the end of COM and EXE files that are executed or closed. When an infected file is opened, the viruses disinfect it.
In some cases "WpcBait.3072" formats disk sectors. Depending on the system time and their counters both viruses display the texts:
a l a - e h !
xxxxx x xxxxx xxxxx x x
|XxxxX|X |XxxxX xx |Xxxx |XxxxX
|X--+X|Xxxxx|X--+X |Xxxxx|X--+X
++ +++----+++ ++ +----+++ ++
------ A.R.Jr W P C B A T S -------
