I got the big tippy one that you put treats in it, ostensibly for my big boy to keep him from tearing the house apart. But guess who has fixated on it? THE TERRIER. And guess who minds his manners while she defends the Kong? THE BIG BOY! She's obsessed with defending it, and preventing him from approaching, which means she lays nearby, and keeps him at bay. she forgets to bark at passerby, she forgets to play, she forgets everything. So he hangs out on the couch and stares soulfully at her. House was in perfect condition 2 days running when I got home!