Grindcore and Grind are seperate entities, only similar in aesthetics. Grindcore and Grind are both made by the same type of people, however, grindcore peope listen primarily to hardcore punk, while grind guys listen to deth metal. They are both horribly awesome styles, and have similarities. It's really hard to tell them apart sometimes.
In a way, they both somewhat stem from metal, but technically, Grindcore isn't metal, as it has a punk musical basis.
Mallcore (Slipknot, SoaD and others like that) is a really watered down version of Hardcore, and is partially related, musically, to grindcore. Deathmetal (Death, Morbid Angel) is similar to Grind.
---
Do you want ants? Because that's how you get ants.