Dungeons And Dragons

D20 Dice Rolling

In the game Dungeons and Dragons?

Im looking for a thing I had once but lost.
It was a chart that if you rolled a 1 on d20 dice roll for attack you then had to roll 2d10 and the outcome good or bad was on the chart. I think im getting it right but not positive.
Does anyone know what its called?

That there’s your “fumble chart”

D&D Dice vs Chinese Spheres – variations in rolling howto #6