  We discuss coin-weighing problems with a new type of coin: a chameleon. A
chameleon coin can mimic a fake or a real coin, and it can choose which coin to
mimic for each weighing independently.
  We consider a mix of $N$ coins that include exactly two non-real coins: one
fake and one chameleon. The task is to use a balance to find two coins one of
which has to be fake. We find bounds for the number of coins for which we can
find a solution in a given number of weighings. We also introduce an important
idea of solution scaling.
