Death Sentance

How about strapping someone to a table and placing some fast-growing Bamboo plants under the table? In short, the plants would grow straight through the table and through the person in a few days.

Another way, that has been used for real long ago, is so do the same table thing, but someone puts a large plate on them that they put one weight on every day that passes. So after 10 days, they might have 40 kg on them, and they get food and water all the time. Eventually, their body won't be able to hold the weights and will be crushed like an egg.