The Invisibility Flowers were at first normal flowers but Kryptonite enhanced them making them different than normal flowers and could refract light that hits it and turn the user invisible to the human eye utilizing cloaking abilities.
Season One[]
The Invisible Man wielding sword using his invisibility powers
Jeff Palmer took the flowers from Lex's green house and covered himself in their oils, becoming a meteor freak. He used the power to get revenge on his sister, Amy Palmer's, tormentors. Chloe took a sample and tested it, making her hand invisible. After Lex rejected Amy, Jeff tried to assassinate him, but Clark saved him and defeated Jeff, taking away his powers.