Slime was a toy product manufactured by Mattel and introduced in the winter of 1976. Slime consisted of a viscous, oozing green material made primarily from guar gum and sold in a plastic trash can. Different variations of Slime were released over the years, including Slime containing rubber insects, eyeballs, and worms and Masters of the Universe Slime for Hordak's Slime Pit playset in the 1980s.
The late 1970s also introduced a Slime Monster board game; the object of the game was to avoid having your game piece slimed on by a foot-tall plastic monster that had slime oozing from its mouth. Other toy companies have produced their own slime such as the 'Ecto-Plazm' sold with select figures in Kenner's Real Ghostbusters toyline. Playmates' Teenage Mutant Ninja Turtles figure line also had Retro-Mutagen slime sold in containers and included with playsets.
What's it worth? Take a look at this Ecto Plazm price guide: sold listings for a value indication.