The child will knock on an unsuspecting victim's door, but before the victim has time to answer, the "knocker" will dissapear in similar fasion to a ninja.
Tyrese: Yo brotha, let's go ninja knocking.
Tyrone: Wurd up dawg, ima say we get the ol' bitch down the alley.
Tyrese: Hellz ya mother fool
Something that occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignited by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.