1900, perhaps suggested by blob, gob, etc. Also compare glop.
Entries linking to glob
blob n.
"drop, globule," 1725, from a verb meaning "to make or mark with blobs" (early 15c.), which is perhaps related to bubble. The same noun was used 16c. in senses of "a bubble, a blister." Related: Blobby.
gob n.1
"a mouthful, lump," late 14c., from gobbet.
glop n.
"inferior food," 1943, imitative of the sound of something unappetizingly viscous hitting a dinner plate.