Video game company Electronic Arts Inc. saw sales plunge below expectations for recently released “Star Wars Battlefront II”. Gamers have pushed back against its in-game loot box purchase system. Photo credit: Jennie Book/Shutterstock.com.

In the past year, gamer forums have been flooded by the discussion of one of the most controversial aspects of the gaming industry—the use of loot crates.

Loot crates, also called loot boxes, are an increasingly common in-game purchase system. Players use real money to buy a box full of virtual items, without knowing exactly what the box contains.

Depending on the game, the items can range from a simple new outfit for a character to a valuable weapon or armor that seriously boosts gameplay ability. And players can spend hundreds of dollars trying to win an item they have a minuscule chance of actually receiving.