Mind Compulsion is an ability of immortals, Original vampires, vampires and hybrids to control the mind of another simply through eye contact. Witches and sirens can also use this power though spells and physical touch, respectively, to facilitate a similar action. Thus far each species have been shown to have the ability to erase the victim's memories or even alter them to the point where something is completely different about them.
Compelled beings usually follow the instructions given to them by the vampire who compelled them to the best of their ability, sometimes even those that would otherwise be beyond their "normal" capacity (i.e. being forced to forget a very recent and otherwise unforgettable experience, cause them to develop new skills, and even create new personalities). Needless to say, this ability plays a vital role in keeping the existence of vampires (and by extension, other supernatural races) hidden. While most vampires use compulsion with verbal commands, this is not heeded as a necessity, as in one such instance Damon was able to compel Caroline with eye contact alone. However, this method of compulsion has not been used since. Silas however seems to easily do these feats without eye contact or verbal commands when he wants, and can even get into the minds of the Original vampires.