Carnifex
A Carnifex is a Tyranid monstrous creature from the Warhammer 40,000 game. A huge and terrifyingly strong monster, the Carnifex often serves as the primary damage-dealer of a Tyranid army list, and is among the most customisable of Tyranid units, allowing for many different varieties of Carnifex to fulfil different roles on the battlefield. They can even be upgraded with regeneration - a mutation previously unique to a Carnifex special character known as Old One Eye, but later introduced to the standard Tyranid army list - making them extremely difficult to kill. 40k players commonly name specific variations of Carnifex by taking another word that represents the concept and appending "-fex" to the end - for example, the Dakkafex is a shooty Carnifex based on the Ork term "dakka".
More tricksy Tyranid players may attempt to use Carnifexes as decoys to draw enemy fire when their smaller units actually present the greater threat to an enemy, as opposing players are apt to focus fire on the Carnifex to attempt to destroy it before it can do serious damage.