Batter picks up live ball

[Forest Ump]

Originally Posted by falsecut

Passed ball Runner on third scores. Man on second moves to third. The
throw from the cather to the pitcher on the play at home gets away and
the batter pickes up the ball. I was the field ump. I saw it called
dead ball. We then called the batter out. Was this correct and what
rule cover this.

The rule book(s) list every way a player can be out. This one isn't in there.