When we were kids I convinced a girl to eat mud because it would make her live forever.
How did you convince her to eat mud that's going to make her live forever?
I lied about it
You shouldn't lie to people because it's immoral. You are lucky she didn't have any health issues from eating the mud. She could get sick or even die and you would have to live with the guilt.
It's only a harmless lie and it's between us. People eat shit all the time and no body bothers.
Still, how would you feel if someone made you do something like this? Don't you feel you might be foolish or hurt?