In 1988 with the larger first series ghost figures and larger Gooper Ghosts already on the market Kenner created and sold smaller Mini ghosts. Which are different, separate, and more affordable ghost figure sets. At $4.99 USD, (1980s dollars, nice) even your allowance money made these obtainable toys.
Kenner’s Ecto-Plazm toys had already reached a crescendo when they created and sold their large Gooper Ghosts. Their’s only so many individual cans of Ecto-Plazm your parents are willing to put up with. In childhood I never had anywhere near as many cans of toy slime as I do in adult hood. I owned more cans of Play-Doh. You know, the less messy play time. They came up with three smaller ghost toys, The Mini Gooper Ghosts,™ Mini Shooter,™ and Mini Traps.™ They could have all come with Ecto-Plazm, but then Mini Goopers wouldn’t be as special.