[s18e5] Episode #18.5 Official

If you are looking for a show specifically using the notation (often used for mid-season recaps or specials), it likely refers to one of the following:

Jeremy Clarkson and James May explore the history of Saab, highlighting its engineering eccentricities, such as the ignition being located between the seats and the company's roots in aviation. [S18E5] Episode #18.5

Episode 18.5, "Recollection," is similarly a compilation episode summarizing the first half of the Alicization arc. If you are looking for a show specifically

Matt Smith, then the lead in Doctor Who , joins the show to set a lap time on the Top Gear track. highlighting its engineering eccentricities