Psychic knife

A psychic knife is a concept featured in comic books published by Marvel Comics. It is associated with the X-Men line of titles and is a power possessed by the mutant super-hero Betsy Braddock, aka Psylocke. A psychic knife is a manifestation of Psylocke's telekinetic and telepathic energy, which she can focus into the form of a blade. The blade does not do physical damage to a target, but rather strikes at them on a psychic level, causing one helluva headache.