Go to the episode were Jack needs some sleep. Now go to the part where Jack is getting in the hammock. The ground starts to sink. What is up with that???
I noticed this too, but this definetly isn't a slipup!! See, the ground is padded and stuff because Jack keeps falling out of the hammock. Don't you think it would hurt if he fell on the actual ground? It's padded to soften the blow, and to make sure he didn't hurt himself.
Yea I noticed this one a while back. It's just fake grass, because I noticed that it ruffled up and stuff. I seen something like that on Growing Pains, with snow. Kurt Cameron was walking through some snow and the "blanket" of snow lifted with his foot. lol