Is it permissible to create a topic in a forum in the name of a person and claim his death, then reveal that he did not die and that the intention was to raise awareness about death and the Day of Judgment?

Claiming the death of someone who has not died, and fabricating untrue stories for admonition and parables, if the reader believes them to be true, is considered a lie. However, if the story is clearly fictional and untrue, and intended for remembrance or to provide examples, then we hope there is no harm in it, though refraining from it is preferable.