help i dont know what the part is called

What is your question?

so i was changing the starter with my stepdad and we took off the top part of the intake and left it there and closed the hood for the next day and when we put everything back together i noticed a piece broke off right under the intake manifold that connects to the engine so now i have to replace it it but i dont know what its called. it looks like a little plug that connects right to the engine and looks like itsfor coolant.