Spawning criteria - grassy terrain in all highfield, arctic, and magnetic biomes in dark areas, spawns alone
Behaviour type - hostile
Health pool and Damage types - medium health pool, weak to pierce, strong against slash
Attacks - latching onto the player, draining stamina
Description - The Swet is a persistent pest in the Aether’s highlands. It hops around, looking for larger creatures for it to latch onto and drain their stamina. If it latches onto the player an on-screen effect and a small model will appear on them to signify that they have a Swet attached, while attached a Swet will rapidly drain the player’s stamina either until it is full, or the player detaches it by jumping into water. If the Swet is able to fill up completely, it will detach on its own and be visibly slow and full. If the Swet enters water its outer shell will dissolve leaving it unable to attach to players. They drop swet gel and rarely sugars, which can be used to craft swet jelly.

Swet.zip
I wont be able to finish the Swet assets before I go away for a week so here's what I have so far, no animations are done but the animations in 1.12 worked nicely so if someone wants to attempt to implement this they can go ahead and I can update the assets once I'm home again