The Slingshot is the first tool that can be obtained in Phoenotopia and Phoenotopia Awakening. It is given to Gale by Alex in the Duri Forest at the entrance to Anuri Temple. It launches small stones and is primarily used to hit switches that Gale can't reach on her own, but it can also be used as a weapon. The Slingshot is pretty weak and only stuns most enemies, but it will instantly kill especially weak enemies such as Slimes, Cave Jellies, and Bats. Spiders also take damage from the Slingshot, and can be killed in 12 hits by it. It deals 1 damage, as has been revealed by Quells on his blog. For comparison, the Wooden Bat deals 10 damage with a non-charged hit.
Interestingly, firing the Slingshot multiple times at a Toad will eventually trigger its death croak, even though the Toad never dies.
The Slingshot is also the weapon needed to defeat the Monster Toad. Gale uses it to knock Duri Fruits out of the trees so they hit the boss and cause him to turn around in confusion, leaving his weak point exposed long enough to deal damage.