KillerMan.EXE

EraseMan.EXE, known as KillerMan.EXE in Japan, is a cyberdeleter NetNavi that is operated by Dark Scyth in Mega Man Battle Network 6: Cybeast Gregar. Specializing on assassinating Navis, he has special abilities such as turning his body into mist and approach his victims without being noticed.

(Source: Mega Man Knowledge Base)