Based on the object:
* "I'm going to the trunk store to buy a new suitcase." (This is a play on the word "trunk" as a suitcase)
* "The elephant's trunk was so long, it could reach all the way to the snack stand!" (This is a play on the word "trunk" as a part of an elephant's body)
* "I packed my trunk full of clothes for my trip." (This is a play on the word "trunk" as a storage compartment in a car)
Based on the sound:
* "My car trunk was making a lot of noise, so I had to take it to the mechanic." (This is a play on the sound the trunk makes)
* "The elephant's trunk was trumpeting loudly." (This is a play on the sound the elephant's trunk makes)
Based on other meanings:
* "I'm trying to get rid of my trunk of old clothes." (This is a play on the word "trunk" as a collection of things)
* "He was the trunk of the family business." (This is a play on the word "trunk" as the main part of something)
These are just a few examples, and there are many other ways to use the word "trunk" in a pun.