Braindead (1993)

Directed by Peter Jackson (of 'Lord of the Rings' and 'King Kong' fame!).

Lionel lives at home with his mum. He falls for Paquita, a girl who's parents own the local shop, much to his mothers distaste. On a secret trip with Paquita to the local zoo Lionel's mum, who was following them, is bitten by a rat-monkey. The bite infects his mum who becomes undead. The movie is both hilarious and gory, following Lionel torn between his new love and his mother with undeadly consequences.  

Theres a particularly 'oh my God' scene, where Lionel is fending off a horde of hungry undead with of all things a lawnmower! for at least 4 minutes of real time. All in all I love this film if it wasn't so funny I'm positive it would have been entirely banned.

Lionel during the lawnmower incident

An undead baby, product of a zombie nurse and zombie priest.