Looks like some sort of tap.
I have seen things that looked like that and were hooked to a water line and your pet would push on the plunger to get water.
https://www.bing.com/images/search?...ve&simid=608038823748374465&selectedIndex=144
I have seen things that looked like that and were hooked to a water line and your pet would push on the plunger to get water.
https://www.bing.com/images/search?...ve&simid=608038823748374465&selectedIndex=144