A running into; hence, an entering into a territory with hostile intention; a temporary invasion; a predatory or harassing inroad; a raid.

Attack; occurrence.

the act of entering some territory or domain (often in large numbers); "the incursion of television into the American livingroom"

Incursion is a Science Fiction role playing game created by Richard Tucholka and published by Tri Tac Games in 1992. The Player characters are humans abducted by alien slave traders. Together with other, extraterrestrial, slaves, they turn on their captors and kill them.

the mistake of incurring liability or blame

We have used the Biosecurity Council definition. `an incursion is the arrival of an organism within New Zealand after it has crossed the border.'