You Barium.
He simply croaked!
Because he always had a Hell of a good thyme.
Because he wanted to win the No-bell prize!! Sorry, I ll walk out
Scientist A: Are you sure? scientist B: Trust me, I know what i'm doing.
Barium
Because if you can't Helium or Curium, you Barium. (Heard it from Heimerdinger, League of Legends)