The grass boss is found after blowing up a wall in the Grotto (preferably with a boom slime). Once you get into the hidden cave, first, you see a cut scene start. You see a bunch of normal grass slimes in one area. You see each of the 100 have a ! over their head. after 2 seconds when they all show up. Then, after 1 seconds, the !'s fade away and 99 of the grass slimes jump on a cliff, scared. However, one grass slime is brave enough to make a web made of vines. The same grass slime makes a ceiling, both disabling you to escape, and allows the other 99 grass slimes to watch the fight. Then, you here an evil laugh. After that, the cut scene ends, and some epic music plays. A wall closes behind you, so it is best to be prepared first.
You need to bring a lot of food to the fight. At the top of the screen, a green healthbar with the Words "Grass Boss" above it. The boss has 40 HP. Food pops up from a coral (each food makes the grass slime eat and produce a plort. You need to throw the plort at the grass slime to deal 1 damage).
When fighting, he has skills. They are listed below.
Grass Slime Spawn
A vine pops up, holding a Grass Slime. This Grass Slime throws cacti at you, dealing 5 damage to you. To counter this, you need to throw it at the incinerator that is to the left or right of the area.
Two vines pop up and they spin in a propeller pattern. This attack eventually stops within 15 seconds, so don't worry about counters.
A cactus pops up. After 1 second of this cactus appearing, it shoots many thorns, slightly spinning counter-clockwise. This cactus stops shooting and disappears within 30 seconds.
When the Grass Boss is defeated, a cutscene appears. The vines start breaking, with the Grass Slime with a scared face. When the top vines break, all 99 fall down to the floor. Then, the Vine Web breaks, revealing 20 crates. 1 grass slime stays with you, while the other 99 scatter, and eventually, escape. One of the crates has a gold slime.
- If you die in battle, the boss will dissapear, but the cave it was in doesn't, so you can fight him again.
- Jetpacks are defective in the fight, so you can't escape.
- Beating him results in the achievement "Weeding Time"
- The Grass Boss's laugh is identical to Omega Flowey's laugh from Undertale.