Vegetoid is encountered in later portions of the Ruins and will tease the player when encountered.
Vegetoid enjoys eating sweets and will throw cake, cupcakes, chocolate, and candy at the player when encountered. He is absolutely disgusted by vegetables. This is the reverse of Undertale, in which he is an enthusiastic nutritionist.
The player can press the "Dessert" option in the menu to spare Vegetoid, causing all of Vegetoid's projectiles to turn green. The player can also eat Vegetoid, but it will damage the player, unlike it's Undertale counterpart.
1: Vegetoid throws a series of sweets at the player from the top of the screen, causing damage when hit.
2: Hundreds of specks of sugar will rain from the top of the screen, bounding around the hitbox.
Flowey: Vegetoid ignores Flowey throughout the entire fight.
Frisk: Vegetoid is neutral toward Frisk, and that can be changed via ACT options.