Possible Clues:

• Gag item floating in Halloween punch
• Turns up, two lines at Abbey empty at back of theatre and in sight of the viewer
• Look at (informal)
• Keenly observe what's in orbit
• Observe energy's needed to lead the old dance
• Stare fixedly at London landmark before dance
• Where to find the sclera, retina and vitreous humour
• Deliberately tried to leave place where you'll find the pupil
• Stare at (colloquial)
• Stare at (informal)