2000-P Sacagawea dollar double-denomination, struck on a 2000 Maryland Quarter. The designs of both coins are visible, with traces of the quarter design visible under the Sacagawea dollar's design. Also, the coin has a reeded edge, which is from the quarter.
The error occurred when a 2000 Maryland quarter was fed into a press striking 2000 Sacagawea dollars and was struck, resulting in a coin with two designs, and struck on the clad metal of a quarter.
This is the most available of the Sacagawea dollar double-denominations on state quarters, although still very scarce with only about a dozen examples known.
MS65 with a hint of steel/gold toning.