PLC's muck up day, with a tradies theme.

The pranks were watered down as year 12s at Presbyterian Ladies' College enjoyed their celebration breakfast yesterday. Photo: Joe Armao

HUMORIST Danny Katz's latest novel is set around year 12 muck-up day.

A greased pig wearing a sumo nappy is released in the school yard, girls wearing Britney Spears costumes zip around on scooters, teachers' cars are flipped sideways and shaving cream is squirted everywhere.

''In my book it's just a complete war zone from start to finish,'' Katz says. But these days the sort of muck-up-day high jinks described in Katz's novels are mostly fictitious. ''I don't think it's done any more. It's all changed now, it's a new world,'' Katz says.

Certainly muck-up-day pranks gone wrong in recent years, including the infamous Xavier College ''jock ball'' and egging incidents, have prompted a rethink of the way schools commemorate the final day. For starters, the name has changed to Celebration Day at most Victorian schools.

''Most schools used to call it muck-up day, but we saw that as being something negative,'' says Presbyterian Ladies' College year 12 co-ordinator Annette Hall. ''A celebration is a much more appropriate way of marking their end of schooling.''

Yesterday's PLC year 12 ''celebration breakfast'' had a tradies theme - a homage to the tradespeople who turned the school into a construction zone during the building of the school's new learning resource centre.

School captain Miranda Zhang says students created overalls and vests from their uniforms and came to school armed with toy hammers and caution tape.

The year 12 girls screened a video to the school featuring Gangnam-style dancing in the quad - ''something very 2012'' - and the PLC pipes and drums band played the bagpipes at their local Hungry Jacks.

Last night was the valedictory dinner with its light-hearted awards - the human microphone, most likely to become the next Einstein, most likely to become the next WAG - while today is the formal year 12 leavers' assembly, where every student is presented with a Bible and a reference.

''It's a massive two days - it's a very sentimental time,'' Miranda says.

Keilor Downs College spreads its dress-up days over three days. Yesterday, Hashela Kumarawansa went to school dressed as the Disney character Pocahontas.

Today, the costume incorporates a bastardised version of the school uniform and tomorrow is the beach-themed Big Day Out. ''It's a surprise the teachers organise - me and a few friends are going as sailors,'' Hashela says. ''It's fun, fun, fun and then my Japanese oral on Thursday.''