This is really cool.
1 go to gmod
2 join a sandbox or go singleplayer.
3 spawn the explosive barrel from the useful construction props
4 also spawn a bunch of cans from useful construction props
5 freeze the explosive barrel
6 put all the cans on with the physgun, freeze them so they stay on.
7 wield all the cans to the explosive barrel.
8 now click on the trails tool in the tools section at the bottom
9 now click on every can with the trails tool
10 now put a balloon on the explosive barrel.
11 unfreeze everything.
12 watch the barrel go up high
13 THEN BLOW IT UP