Having gotten accepted on part 1, here I go:
Who am I? You'd like to know, so please just ask who's there,
You might have a laugh on my account, I don't really care,
If not it's still OK, that's something I can bear,
I come right out no need to guess or speculate your share.
Edit; Two more lines which might be sort of a giveaway, I'll leave them as a hint:
Your cooperation is required, don't leave me out your lair,
I am right here behind the door, respond my tapping fair.