(Sorry for my bad redaction. I'm writing on a phone)
So I'm presenting the Nether Monkey. I don't have a proper name by now, but I want to share my idea.
This Nether Monkey would have a Piglins like appearence but smaller and with larger arms.
They would be very playful. They would jump around and habit Netherwart forests and sometimes in Piglin Bastions.
They appear to be very friendly but then you find out that is your worst enemy.
He would approach you and examine you. He would decide if they want to bother you or steal you. As Piglins, they are attracted by gold and they would steal your gold related items (and also armour too) When they steal, they would do some damage.
The stealing would be great as you will have to be careful when you want to protect yourself from Piglins or barter gold with them.
However you can gain trust with a Nether Monkey. If you throw some gold nuggets they can stop playing around you or stop stealing. Although you have to be lucky since there is a possibility that they want more gold and steal you more.