What are things people shouldn't put in the trunk of their car?

Bottles of corked wine during the day and in the summer heat and then forget about them until you go back to your car the next day and can smell the booze from over 10 feet away. Yup... in 2015 it happened to me. What a waste of booze. I'm so lucky I didn't get pulled over by a cop.

Dead bodies without dry ice

Open container of molten metals

African Fire Ants

Babies, explosives, large lead ingots, sacks of cocaine, illegal porn

Soda and that's all I'm saying on the subject..????????

Bodies
Drugs
???? explosives

fragile things

Gallons of gasoline. 

Or if you are Mrs. H.............dead bodies. 

Gallons of pudding

A can of gas - it's dangerous.

Hostages 
Weapons
Explosives

i once put a box of lettuce in the trunk, and i was surprised that in a Portland summer heat lettuce actually can be stored for days. all you have to do is peal off the outer leaves. but for what not to put there, probably "dead bodies" or even kidnapped victims that are awake and alive and kicking and screaming. Too much tv i guess

Dead bodies, half dead people who are bleeding

A bowl of goldfish.
An ice sculpture.
A lit candle.

Stolen goods for a start my friend, not a good idea.