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' anagrammed 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?" .)