The developer used particle physics and a spring system to accomplish this impressive feat.
Solo Game Developer, known as OMYOG, has shared a tweet that demonstrates stunning plant physics set up in Unity. The developer has managed to add natural-looking movement to a Colocasia plant, native to south-eastern Asia, and make it bend appropriately when it is stepped on by the player character.
To set up the physics, the developer used a custom solution. According to OMYOG's explanation, physics are basically particle physics and a spring system, rendered using a custom GPU skinning solution that has fewer features but is more lightweight than SkinnedMesh. The developer also added that this effect is not demanding hardware-wise. The plant itself was made using photogrammetry.
This Colocasia was made for Project Ferocious, the game being solo-developed by OMYOG. PF is a survival shooter in which you will discover a lost prehistoric world full of deadly creatures under the control of hostile forces. Using a plethora of weapons and tools, you will need to survive on a mysterious island full of dinosaur-looking creatures and uncover the truth about the lost world. You can learn more about the game by visiting Project Ferocious Steam page.