First rule of killing slime or splitter creatures: figure out which kind you're dealing with. Besides the notable mistake of the wooden execution floor (BAD), the Candy Kingdom is doing some high-quality science here:>Start by cutting it in half or beheading.
If it doesn't clearly die, chop one of the two pieces in half again. You're looking to see if it's trying to bud into new versions, or recombine.>If it's trying to recombine
You got lucky: Just prevent that and you're probably good. One good way is to chop or separate the pieces into dice-sized hunks of meat or goo and throw'em in a oil drum full of cement, then throw the drum into the ocean whenever convenient.>If it's budding into new versions
Then you may have more serious problems. You've got two main kinds of budders, >full sized new versions>smaller versions of full thing
If it's smaller versions, you got lucky, same strategy: dice sized bits, cement, ocean.
The full new versions case is the real nightmare though: Your execution probably already failed if this is the case, you don't know if this is the last one. Luckily, it probably dislikes splitting or finds it painful, because you thought there was one, and you aren't fighting an army of them.
Since you're not going to know what the smallest viable rebud is, you MUST capture all pieces, or at least enough that you're not letting it make too many new buds.
This means your step the moment you know you have a full-budder is STOP CHOPPING, it only makes the problem worse. Then:>If it's fast, arrest all new buds. >If it's not, your focus should be verifying you've collected as much bone, meat, and viscera from the execution scene as you can, and verifying that others on the scene didn't take any pieces with them. Wooden floors with holes make this harder, don't have them.
Your new goal is finding a destruction method. Try pressure, acid, alcohol, water, ice, and incineration, and see which seems to work. Then do that, a lot.