Mutant tulip bulbs did this? (3,2)
I believe the answer is:
lit up
'bulbs did this?' is the definition.
The definition suggests a singular noun but the answer is not.
'mutant tulip' is the wordplay.
'mutant' indicates anagramming the letters.
'tulip' with letters rearranged gives 'LIT UP'.
Can you help me to learn more?
(Other definitions for lit up that I've seen before include "was illuminating" , "Drunk (informal)" , "Flashing" , "Started smoking - being drugged!" , "like a bulb, perhaps?" .)