The Rare Elemental in a Bottle is a Hardmodeaccessory which has a 5% chance to drop from Sand Elementals in Expert Mode or higher. Equipping it summons a Rare Sand Elemental. While the player is below maximum health, she throws green orbs which home in on the player and heals them for 25 health. These orbs are thrown approximately every 2 seconds.
In the mod's source files, the Rare Elemental in a Bottle is referred to as "WifeinaBottlewithBoobs".
The Rare Sand Elemental projectile was previously called "Drew's Sandy Waifu" in the mod's source. Drew (also known as MountainDrew or Fabsol) is the lead developer of the Calamity Mod.
This item used to be called "Rare Waifu in a Bottle", while the Rare Sand Elemental herself used to be called "Rare Sand Waifu". After that, they were known as "Madame in a Bottle" and "Madame Sandy", respectively.
In previous versions of the mod, the Rare Sand Elemental used the same AI as the normal Sand Elemental minion, dealing contact damage and summoning tornadoes. The summon can no longer deal damage and exists solely to heal the player.