Cresselia

cresselia has a mysterious link to darkrai. she first appeared in diaamond pearl and platinum. she would run around the region.?

in black 2 and white 2, she tried saving the ghost girl in strange house. the ghost girl gives you the lunar feather, since she can no longer use it. she asks you to return it. this is why she would inhabit the bridge, as this is where you could catch cresselia.