Fuel Array

The Fuel Array is a single-use equipment in Risk of Rain 2, added in the Scorched Acres Update.

 Obtaining: 

The Fuel Array can only be obtained during the first stage, by interacting with a hatch on the back of the escape pod that the player spawns from.

 Usage: 

Activating the Fuel Array will cause a short timer, ending with an explosive that is guaranteed to kill the player. Damage is equal to 300% of player health.

Interacting with REX in the Abyssal Depths stage with Fuel Array in the player's equipment slot will unlock REX as a playable character. This will also remove the Fuel Array from the player, as well as unlock the Power Plant challenge.

 Notes: 
 * Falling below 50% HP will also force the array to explode. As such, things like fall damage, Stone Golem lasers, and other high instant-damage sources are more dangerous than normal. Currently, activating a Shrine of Blood using any character with the Fuel Array equipped is a guaranteed death.
 * Certain character abilities that grant immunity frames can be used to avoid the damage entirely, though the item is still lost.
 * It is possible for Tougher Times to proc and negate the damage.
 * Shaped Glass (And presumably, any future items that affect max health via the Curse debuff) can be used, as it modifies maximum health as opposed to being seen as damage dealt.
 * Due to the new drop-pod that MUL-T initially spawns from, obtaining the Fuel Array is currently impossible as MUL-T without playing in multiplayer. This is likely to avoid using his passive ability to stash the Fuel Array into the secondary equipment slot, thus nullifying the danger of detonation via damage sustained.
 * If MUL-T is below 50% Health and switches to the equipment slot containing Fuel Array, this will instantly begin the countdown. This cannot be stopped by switching back to the other equipment slot.
 * If the Fuel Array explodes, either from manual activation or from damage, it will be destroyed and removed from the player's inventory, regardless of any obtained Fuel Cells.
 * In multiplayer, it is possible to obtain multiple fuel arrays, though this can only be done by having another player drop theirs via exchanging it with another equipment item.
 * In multiplayer, if one player uses the Fuel Array to repair REX, only that player will obtain the achievement Power Plant, and thus, only that player will obtain REX. It is possible for multiple players to repair REX with their own individual Fuel Array in the same session.