As noted in the previous post, Yosef's brothers used Yosef's coat and some goat blood to fool their father into thinking Yosef had died. This got me thinking - how common does mistaken identity come up in Tanach?
A partial list:
Sarah pretends to be Avraham's sister.
Rivka pretends to be Yitzchak's sister.
They angels pretend to be human to Avraham.
The angels seem to be human to the Sodomites, and perhaps Lot.
Lot sleeps with his daughters, being so drunk he does not know who they are.
Yaakov pretends to be Esav via Esav's clothing and some goat skins.
The brothers pretend that Yosef's coat and some goat blood are all that remains of Yosef.
Moshe's sister says she will get a regular nursemaid but in fact fetches Moshe's mother.
Perhaps, when Moshe comes to Midian, the girls he saves think he is an Egyptian.
In sefer yehoshua (9:4), the Gibeonites use old clothing and flasks to pretend they are from far away, so as to make a peace treaty.
In 2 Shmuel 14, Yoav convinces a woman to pretend to King David that she is a mourner.
Update Nov 2 2004: I missed: Tamar pretends to be a prostitute to get together with Yehuda.
Update Nov 14 2004: I missed: Yosef presents himself to his brothers as a stranger - as the vizier, which he is, but does not tell them that he is their brother.
If I missed some, please post a comment!