What I expected to happen
I would be able to pick up the item after the mob was dead, since summoning an item (/summon Item) allows me to do so.
What actually happened
I couldn't pick up the items, nor they were gone. They just stayed above the ground, and I couldn't pick them up, even though my inventory wasn't full.
Steps to Reproduce
1. Execute this command:
/summon Silverfish ~ ~1 ~ {Riding:{id:Item,Item:{id:1}}}2. Kill the mob
3. Try to pick up the dropped item. You won't be able to.
In order for that to happen, You have to not define the Count tag. ALWAYS define the tag or you will not be able to get the item.
/summon Item -999 68 1017 {Item:{id:sponge,Count:1},Riding:{id:Silverfish}}
That will spawn a silverfish with a sponge on top that you can pick up, but you also don't have to kill the mob. This can be done, but not as easily.