A glob is a shapeless clump or hunk of something. Even the most skilled potter starts out with nothing but a glob of damp clay on her pottery wheel.
Globs are soft, squishy, or partly liquid substances — you can't really have a glob of pizza, but you can add a glob of melty mozzarella to the top of a pizza. An artist drops globs of oil paint on her palette, and a chocolate maker fills molds with globs of warm melted chocolate. While we know glob first appeared in print around 1900, its origin isn't clear. It may have imitated words like blob and gob.