Catch or Kill (series)
Catch or Kill is an original comic series published in TV Century 21, beginning in issue 90 on 8 October 1966.
The series featured Crag Gorton and his assistant Kipper, who are employed to either catch or kill wild creatures in the universe.
Crossover
Despite being partially published in TV Century 21 - a magazine where all fiction published within shares a universe (including the former The Daleks comic strip), only one work of fiction crosses elements of the Catch or Kill series over with elements of the Doctor Who universe.
This crossover occurred in the 21 feature Agents Observation Test, where readers were asked to answer several questions, with an in-universe framing. One question pertained to the ongoing narrative of the Catch Or Kill comic, namedropping characters such as Crag Gorton and Sheik Ali Barka, while a later question directly referenced the Daleks in a question pertaining to their comic strip.