Where do imaginary friends go... when they're forgotten?

[Lucky]

Well, here are my theories.

When a creator starts to forget about his/her imaginary friend while the friend is living in Foster's, the friend starts to have his/her health decline, and when the friend is completely forgotten, the friend dies.

UNLESS, of course, the friend is adopted. So even if the original creator forgets about his/her friend, the friend, they will still have a new companion.

Though I'm not completely sure what happens when the creator dies first. If I can remember from "Infernal Slumber" (Note: I'm not entirely sure, I last saw this episode in November 2007), when Mac starts shooting his mouth off at Bloo, most of it is inaudible gibberish (was he swearing? Because they used something similar to that in Chowder), but the only thing I could make out was "IF I DIE, THAT MEANS YOU...", does that mean...

Well, Foster's never outright talked about death of anyone anyway, not even pets, as do most shows for the same target audience (well, except for Recess and Rugrats)