Who said "Death is the only certainty except taxes."?

This quote is attributed to Droopy.

Death is the only certainty except taxes. - Droopy

"Death is the only certainty except taxes."

Droopy Death

"I'm so happy."

"Hello, I'm so glad to see you."

"That makes me so sad."

"I'm afraid I have some bad news."

"Death doesn't scare me anymore."

"Death and I are old friends."

"Welcome to my world."

"Death is just the beginning."