Moss giants are fairly large creatures that live in Gielinor. They attack with ranged and are thus weak against melee attacks, with their specific weakness being slash weapons. Moss giants are popular for training, especially on Free-to-play worlds, because they are one of the few creatures that drop Big bones. In addition, as stated before, they are one of the few free-to-play monsters that are weak to slash attacks, enabling players to use slashing weapons such as the rune scimitar and the rune 2h sword to take full advantage of their weakness. Moss Giants are aggressive to players with a combat level of 102 or lower.
They are sometimes given out by Vannaka as Slayer assignments. Food is highly recommended for lower levelled players.
Varrock Sewers (4 moss giants) In free-to-play worlds, there are 2 spots (2 per spot). The spots can be crowded. Since Moss Giants can use ranged attacks, there is a spot behind the Cauldron for Magic/Range users, but they can be attacked there if the Moss Giants aren't aggressive.
Crandor Isle (3 moss giants) This is arguably the best place for free players to kill moss giants as there are three of them and there are rarely any other players on Crandor. Use of the rejuvenate ability can reduce the need for food, but it may only be used once every five minutes.
The Wilderness, north of the pond and the Wilderness Volcano, in the greener area. The easiest way to get here is to use the canoe system which takes you directly to the pond. A few skeletons are wandering around and you can get killed by PKers at any time, so this area is not recommended.
The examine, "Bigger than your average moss giant." is a play on Yogi the Bear's words, "Smarter than your average bear".
A moss giant bone, which differs from the usual big bones dropped by moss giants, is a common drop after completion of the first part of the Rag and Bone Man quest. It is one of the items in the wish list for the second part of the quest. This bone cannot be buried.
There are two slice of cake spawns on the moss giant island near Brimhaven, and on uncrowded worlds, this can often make extra food unnecessary.
There is a pipe that players can access at level 51 Agility right next to Vannaka for easy access to moss giants if they are given as a Slayer assignment. It is a popular place for players to train the Slayer skill.
As referred to Armies of Gielinor, Moss Giants are followers of Guthix.