The Leshy (レーシイ or レーシー, Rēshī?), also known as the Weeper, is a recurring creature in the Final Fantasy series, first appearing in Final Fantasy IV.
Appearances
Final Fantasy IV
The Leshy, also known as the Weeper, appears as an enemy encountered in the Antlion's Den. It is of no threat to the player, as simple physical attacks or even summoning Chocobo will bring it down quickly.
Final Fantasy IV: The After Years
The Leshy returns as an enemy encountered in the Sylph Cave, Mt. Hobs, Antlion's Den, and Challenge Dungeon, as well as the Agart, Underworld, Fabul, and Red Moon regions. It is not a dangerous enemy and can be easily dispatched.
Final Fantasy XI
The Leshy appears as a treant enemy encountered in Lufaise Meadows and Nyzul Isle. Nearby Leshachikha saplings will also aggro if a Leshy attacked, implied to be Leshy saplings.
Final Fantasy XIV
The Leshy appears as a family of tall, treant-like seedkin introduced in the Stormblood expansion. The common Leshy can be encountered as an enemy in 
The Fringes.
Final Fantasy Record Keeper
The Leshy from Final Fantasy IV appears as an enemy.
Final Fantasy Brave Exvius
The Leshy from Final Fantasy IV appears as an enemy during the "Fabul Castle Guard" event.
Etymology
Leshy was a Slavonic trickster spirit that roamed forests and made travelers lose their sense of direction, and protected wild animals and the woods. It also has a wife, Leshachikha, and children, the Leshanki.