This may sound like a weird request but if there's any item out there that can lower a pet's intelligence, can you link it to me? I'm pretty sure it doesn't exist because I did look for one, or perhaps I'm searching wrong.

there (used to be? I can't find it anymore) is a place called the Gym Vending Machine, and kicking it would result in a net random stat loss. One of the stats you were able to reduce down to 1 but no lower was intelligence. Maybe zapping will do it?

There is no Intelligence Leech, and none of the randomly negative boosters affect INT.

I'd never heard of the Gym Vending Machine but I'm totally willing to give it a try and hope for some luck. But is there anything you need to use to kick it? I receive this message:

According to the Subeta Wiki you need to have a pair of shoes in your inventory http://subeta.wikia.com/wiki/Gym_Vending_Machine

PS I found this in a comments thread from 2007 https://subeta.net/news/4012