There was no flashy display and nothing special happened. Lex simply got a notification saying that the Mystery trial would shut down as soon as the guest currently using it would exit, and the upgrade would take a short while.
Lex shrugged and turned his attention to the next token, the 0.5 star increase token. This fella here would be his main attraction to a festival Lex was planning. He checked his MP and saw that he had a little over 20 billion of it, so he could begin his planning.
He opened up the event panel and began creating the event. Basically, Lex was planning a big party and interesting events for a long duration of time. Although his intentions were to genuinely create this event and hoped that it would be successful, that was not his main goal.