One major gameplay element of Realm of the Mad God is dungeon crawling. Players can gain access to dungeons by either killing the monster that naturally drops the dungeon portal, or by a player opening a dungeon portal through the use of a key (often purchased with Realm Gold). Most dungeons are generated with a random layout (though some dungeons do exist with a predetermined layout), so they will have a different layout with every visit. Dungeons range greatly in difficulty, from very easy beginner dungeons like the Pirate Cave or Spider Den, to dungeons like The Shatters and Lost Halls that are considered by the community to be far more difficult than even the fight against Oryx. Most mid-to-high level dungeons will provide the player with stat boost potions, some even guaranteeing such potions in certain conditions. The dungeon monsters also have a chance to drop equipment for the player. In addition to these drops, dungeon bosses typically provide the player with a small possibility of obtaining unique and rare pieces of equipment that cannot be found anywhere else. Some of these rare items may prove more useful to the player depending on their preferences or the type of item. Realm of the Mad God currently has 15 different playable classes. Players begin with only the Wizard class unlocked and successively unlock the remaining classes as they reach level 20 with each class. There are six different weapon types and three different armor types for each class to use. In addition, each class possesses a special ability that is exclusive to that class. Depending on the class, an ability can deal burst damage, inflict debuffs onto enemies, buff allies, heal allies, or perform a defensive function. Items are generally classified into tiers, with higher tier items having better stats. Some items are not classified by tier and are thus either given an "untiered" designation, or a "set tiered" designation if they are part of an item set. Item examples include weapons, armor, rings, abilities, limited use items, and April Fools' Day accouterments. Items are typically dropped in bags when the monster who was "carrying" it is killed. The loot bags come in the following color tiers (lowest to highest): brown, pink, purple, basket, gold, cyan, blue, orange, red, and white. Better equipment is typically seen in a higher tiered loot bag. The rarest untiered items tend to drop in white bags, and are frequently referred to in the community as "white bag items" or "whites" by this association. Many of these "white bag" items can completely change the way a class is played, and are highly sought after by players.