hidden ball trick; ace up one's sleeve; secret weapon
glass sphere; glass bead; glass marble
junk ball (pitch); off-speed pitch; unexpected move; unorthodox measure
one's repertoire of pitches; balls at hand (in pachinko)
wild ball (usually a pitcher with poor control)
ball won in a game of pachinko
bait pitch; sucker pitch; pitch that lures a batter to swing
droplet of oil floating on water