Topps has been featuring the mascot cards in Opening Day for quite a few years now and I have yet to get tired of them. I have never consciously tried to complete a team set from this release but do like adding the mascot cards to the flagship team sets. If getting younger kids interested in baseball cards is a goal of the card manufacturers, then these inserts are a great place to start.
One of baseball's most popular mascots, the Moose debuted in April of 1990. A contest had been held to determine what the first Mascot in team history would be, and the Moose had narrowly edged out (reportedly by one vote) Seaward the Seamonster. Children 14-years and younger from around the Pacific Northwest had submitted over 2500 entries, and among the finalists were Bernie the Mariners Mongoose, Mightyball, the Mariner Seal, and Mr. Mariner (no other details given). Want to rent the Moose for your party or corporate event? You can- for the right price. According to a 2013 Wall Street Journal article, the Moose is among the top 3 most popular baseball mascots and can be rented for $600 per hour, a price in the same neighborhood as the top 2 (Mr Met and the Phillie Phanatic).
Thanks again for the trade, Laurie. Will have to definitely exchange some more cards in the future.