If he was truthful, then let him bring himself back to life...

Jundub ibn Ka'b, the Companion, killed a magician in the presence of one of the governors of Banee Umayyah. He came and found the magician playing games in front of the governor, pretending to kill a person and then bring him back to life by cutting off his head and then replacing it. This is a kind of illusionary magic. He was trying to convince the people that he was killing him and then putting his head back upon his shoulders. He did not actually do anything, he was only tricking the people with an illusion. So Jundub went up to him and struck him with his sword until he chopped his head off, and said, "If he was truthful, then let him bring himself back to life."

Translator: Ibn 'AbdilBarr (may Allaah have mercy on him) mentioned that the governor was al-Waleed ibn 'Uqbah (may Allaah be pleased with him), and that he arrested Jundub for this action and wrote to the khaleefah 'Uthmaan ibn 'Affaan (may Allaah be pleased with him) about what happened. 'Uthmaan then ordered him to be released and he was. [Alistee'aab, p.113]

Nawaaqid al-Islaam