Sesame Street Mini Beans were a series of twenty-four small (usually less than 4") bean-filled plush toys based on the 1997 Tyco Beans. A Baby Natasha mini-bean was substituted for the Purple Honker full-size bean; all other characters appeared in both sets.
The promotion spanned six different cereals -- Kellogg's Smacks, Rice Krispies, Corn Pops, Apple Jacks, Frosted Flakes, and Marshmallow Blasted Froot Loops -- and each of the six cereals was assigned four toys from the set. Because the customer didn't know which toy was in the cereal box, collecting the full set of 24 required buying (and presumably eating) dozens of boxes of sugar cereal. (Customers could also send 24 UPC codes from the boxes and mail them to Kellogg's for a full set of Beans.)
Kellogg's Sesame promotion marked the company's return to "in-pack premiums", which it had dropped in 1995. At the time, the Sesame Beans were the highest-value premium in the company's history. 
Similar mini-beans were also sold in Singapore in 1999 as a McDonald's Happy Meal promotion.