In hyperbolic use: To come near to killing. To overwhelm (a person) by a strong impression on the mind, as of admiration, astonishment, alarm…

to knock sideways: to astonish or dumbfound, as with pleasure or shock; to affect profoundly or dramatically.

to blow (a person's) mind, to induce hallucinatory experiences (in a person) by means of drugs, esp. LSD; hence transferred, to produce (in a…