Each jungle camp's large monster buff can be taken only once.

So basically, if you smite the Krugs, then you take the "Gift of Heavy Hands" buff, and the second person to smite it will not get the buff.

More importantly, this works with Raptors and Wolves. This makes it so that you get the vision buff without actually finishing the camp. You could just kill the large monster of the camp, but that way if anyone other than jungler comes by they will try to clear the rest of the camp. Just smite the enemy raptor and ward dragon/baron. That way, you know their jungler can't clear those wards.

This is some new level of counterjungling. The enemy will probably think it's a gamebreaking bug.