In my ongoing Pathfinder Roleplaying Game campaign, one of the only original characters left (since we started the Second Darkness adventure path) is Gadak - a half-orc wolf shaman druid. The main problem my player ran into was that eventually his animal companion grew to large and was having trouble fitting where Gadak wanted to explore. So he created these.
Aura faint transmutation; CL 3rd
Slot neck; Price 8,000 gp; Weight 1/2 lb.
When placed upon the neck of a willing animal this collar causes the animal to be instantly diminished, halving its height, length and width and dividing its weight by eight. This decrease changes the creature's size category to the next smaller on. The animal gains a +2 size bonus to Dexterity, a -2 penalty to Strength, a +1 bonus on attack rolls and AC due to reduced size but all natural attack damages drop one category. Any other equipment worn by the animal is likewise reduced. The animal remains reduced until the collar is removed with a full-round action.
Requirements Craft Wondrous Item, reduce animal; Cost 4000 gp.