Ricin.
It's an extremely EFFECTIVE poison.
Breaking Bad Season 2, Episode 1
I always considered your father
a very EFFECTIVE and efficient man,
Game of Thrones Season 7, Episode 4
I was able to take
an EFFECTIVE shot.
Breaking Bad Season 2, Episode 3
Placinex proved
extremely EFFECTIVE in treating
The Big Bang Theory Season 9, Episode 12
...which are only EFFECTIVE against
wraiths and daywalkers...
The Big Bang Theory Season 3, Episode 5