A panikhida is usually sung over a dish of kolyva, boiled wheat mixed with honey and often with nuts, raisins and pomegranate seeds, decorated and set on a table with a candle in it. It is blessed during the service and eaten afterwards, shared among those present. The explanation given for it in the service books is a scriptural one: a grain of wheat has to fall into the ground and die before it bears anything. The dish is an argument in food, and it is eaten rather than merely displayed, which is a fair description of how the tradition handles teaching in general.
The custom of the wheat is old and has local names and recipes across the Orthodox world: koliva in Greek usage, kutia in Slavic, where it is also a Christmas Eve dish, and versions in Romanian, Serbian and Georgian practice. The details vary and the meaning attached to it does not.
Radonitsa is the strongest expression of the same idea. On the Tuesday after Thomas Sunday, in the second week of Pascha, Slavic Orthodox families go to the cemeteries, and the memorial is sung at the graves with the paschal greeting, "Christ is risen", and with red eggs left on the stones. The name is usually connected with the Slavic word for joy. The practice absorbed older spring commemorations of the dead in the regions where it took hold, a continuity that scholars of Slavic religion note and that the church has never treated as a problem.