Because he was feeling crumby.
or
By paying them to cheer for him during campaign events.
or
When a rooster wakes up in the morning, its primal urge is to cluck defiance.
or
Because an undocumented worker has been living on his head for the past 2 decades!
or
Only one. But he'll leave a big puddle of spit on the floor underneath him.
or
Shamboo!
Frankenstein: Witch can you make me a lemonade?
Witch: Poof you are a lemonade!
or
Bozo The Clown has real hair on his head.
or