The generic epitaph, found on many tombstones and used heavily in cartoons. Usually said to be short for "Rest In Peace", "Rest In Perpetuity", or "Rebirth in Progress". The original meaning is Requiescat in pace, a Latin phrase meaning "May s/he rest in peace".
Today it's usually used just to denote that something is dead, and will be missed. e.g.: dayloghelpermonkey, R.I.P.