Graham O'Brien's psychic paper
From Tardis Wiki, the free Doctor Who reference
The Thirteenth Doctor gave a piece of psychic paper to Graham O'Brien as a parting gift. When Graham and Ryan Sinclair learned about rumours of a troll invasion in Finland and gravel creatures in Korea they decided to eventually investigate that. Graham and Ryan were planning to use their psychic papers as they "[would] get [them] anywhere". (TV: Revolution of the Daleks)