Help with Shrink Item

[shadowevor]

My players are always looking for special ways to make good use of spells......

Now there is a question. Could someone cast shrink item on a barrel of ale, persuade the victim to drink it, and send a command to let the wine restore to its volume? Even if he drinks only 0.1 gallon, the ale in his body would restore to 400 gallon, enough to make a big explosion......
Is that possible?

Another similar question, what if the caster cast shrink item on a rock, and throw it into a narrow corridor, just fit with the size of the rock. When the caster command it to restore or the spell wear off, what happened then? The wall and the rock start competing hardness?

 

[Dandu]

Shrink Item does not say, but Enlarge Person states that if a person is too large for his surroundings, he simply stops growing. He gets a strength check to break through his restraints, though.

Feel free to extrapolate from that what should happen to the victim. Perhaps constitution or strength check?

The rock would probably jam the corridor.

 

[Jhaelen]

Now there is a question. Could someone cast shrink item on a barrel of ale, persuade the victim to drink it, and send a command to let the wine restore to its volume? Even if he drinks only 0.1 gallon, the ale in his body would restore to 400 gallon, enough to make a big explosion......
Is that possible?

Nope, the expansion does not exert any appreciable force.

Another similar question, what if the caster cast shrink item on a rock, and throw it into a narrow corridor, just fit with the size of the rock. When the caster command it to restore or the spell wear off, what happened then? The wall and the rock start competing hardness?

See above. The expansion will simply be interrupted until there is enough room.

A similar question is regularly asked about Quaal's Feather Token (Tree & Ship). There is no way to (ab)use them to kill stuff, either.

I guess, there might still be DMs allowing this kind of stuff in their games, but I'm definitely not one of them