Place your chocolate bar on a cutting board. Chop it into small, chip-sized pieces with a sharp knife. Smaller pieces melt faster and more evenly, which saves you time.
Pour about two cups of water into a pot and heat it on medium. Choose a mixing bowl that sits snugly on top of the pot. Make sure the bowl is completely dry before you add the chocolate.
Add the chopped chocolate to the bowl and stir it now and then as it melts. Keep every drop of water away from it, because even one drop can make white chocolate seize. Once it looks smooth, lift the bowl off the pot.
Set the bowl aside for a few minutes. Chocolate that is too hot runs right off the berries and leaves thin, patchy ghosts. When it feels warm instead of hot, you are ready to dip.
Wash the berries and pat them completely dry with paper towels. Trim off the green tops so each strawberry has a flat cut side. That flat side will become the ghost's base, so it stands up nicely.
Pick up a strawberry and dip it fully into the melted chocolate. Turn it so the white coating covers every side. Let the extra chocolate drip off for a moment so the ghost looks smooth.
Place each dipped strawberry cut side down on the parchment-lined tray. The base should rest flat so the ghost stays upright. Work quickly, because the chocolate begins to firm up fast.
Use tweezers or clean fingertips to press two chocolate sprinkles onto each ghost for eyes. Do this while the coating is still soft so they stick. Leave the tray at room temperature until hard, or slide it into the fridge to speed things up.