1) The Swinging Chad
Size: Human
Found: Central, Northern, Circle lines
Breeding times: 8-11AM, 5-7PM weekdays
Behaviour: The Swinging Chad is a much-misunderstood creature. Locating itself firmly in the doorway of a half-crowded carriage, it then remains rooted to the spot, no matter how many people subsequently try to embark or disembark past them. As a result, Swinging Chads are generally mistaken by the ignorant for rude, arrogant tossers who feel it beneath themselves to get out of other peoples' way. But nothing could be further from the truth, as these limpet-like animals are as much a part of the underground system as a broken 'service update' board or posters of MacKenzie Crook's knackered face.
Life Cycle: Swinging Chads have a short lifespan. Hatching from eggs laid down the backs of carriage seats, they first emerge about 4AM and have reached full maturity by the time the train comes into service. After mating with another of the species (who is then devoured) they enter incubation stage, fusing an arm-like tendril to the ceiling rail of the carriage, and on foot-like appendage to the floor. The location commonly chosen - right in front of the doors - is hazardous, but necessary to provide adequate cooling. By 11 o'clock the eggs are ready to be laid in the approved manner, and after this the Chad crumbles away to nothing. The eggs will either hatch next morning, or occasionally in time for the afternoon rush hour. Chads are edible, chickeny, and high in Omega 3 oils.