Stir together marshmallows, sour cream, shredded coconut, drained crushed pineapple, and halved grapes. Pile into serving dish. Garnish with grape halves and canned mandarins. Let sit several hours or overnight.
The amounts can be varied. The mini marshmallows make up the bulk of it. I used a small bag. There has to be enough sour cream to moisten it. Maybe two cups? A couple handfuls of shredded coconut out of the jar. A can of crushed pineapple was partially drained. The moisture absorbs into the marshmallows. Heaping double handful of green seedless grapes. The drained oranges could have been mixed in but I chose to decorate with them instead.