Can a judge or prosecutor be called as witness?

What is the name of your state? IN
Has it ever happened where a judge or prosecutor be called as a witness at a trial unrelated to them?

Yes. If either witnesses a crime or accident, they are a precipient witness and can/will be subpoenaed to appear in court.

Per Judicial Canons (Rules) it is an ethical violation for a Judge to appear in a civil case, as a character witness, without being subpoenaed.

Thanks for the info and for answering promptly!