In Infinite Stairs, which Pet Items unlock the Explorer and the Ballerina?

I'm asking about the mobile game Infinite Stairs.

Under unlockable characters, there are two characters which are unlocked after you have used a certain pet enough so it gets a new item. You can see the picture of the items you need; however, you don't know which pet gets that item until after you buy the pet. So, my question is: does anyone know what items those pets belong to?