Are you talking about any of the four Monster Blood books or The Blob That Ate Everyone? I never liked the latter as a kid, the magic typewriter seemed cliched even back then as did the convenient ending. I think I enjoyed Monster Blood I - IV more out of obligation, the sequels basically just went full Honey I Blew Up the Baby.
Goosebumps
Ian Baker
Austin Smith
I dont remember which one, it is about a kid that buys a can from a "magic" store and then this shit gets bigger and bigger and some time later the slime eats a witch, and this somehow kills the slime if I remember correct
Jordan Gutierrez
MoruQQQQQQ
Ich hab kein Datenvolumen mehr kann mir bei Vodafon jemand schicken wo noch was hat