So years ago when I started out D&D the party I was in was on a retreval mission which led us to a castle. Going by the information this was were the item was. So we go in and fight the usual monsters, until we come across a locked door. It could only be opened with a key and any other method would result in the castle coming down. So the party looks around the castle and in the stables we see a giant hamster that has a key around it's neck. My character notices a chandelier above it. Him being a rogue he could easily pull this off and sneaks in the room and goes to the rope holding it.
Another PC, thought it would be better to just kill the thing without thinking and charges in. As he got closer the DM asked him to make con saves. Player doesn't know why. But if you've ever owned a hamster, you find out that they aren't the most clean of critters. The smell is too much as he is a foot away and reacts in disgust. The giant hamster wakes up and sees him, attacking instantly with bite.
The rest of the party jumps in except for mine, why? The party was mostly a good party, excluding me since I wasn't comfortabe with other allignments at the time other than Chaotic Neutral. They would scold my character for doing bad things for selfish reasons. Well, this was where all that scolding would come back to bite them, litterally.
The giant hamster wasn't just a giant hamster, he could summon packs of minions. So my character is just sitting pretty as this unfolds, enjoying it as he considers it payback for the party's finger wagging as the rest of the party is being devoured by small hamsters.
The party eventually dies by being eaten alive as my character makes his move of cutting the rope and killing the big hamster. How was it so easy? Bladed bottom of the chandelir and it was high enough to work better than an axe.
My character gets the key as the small hamsters scatter, but one remained since his leg was broken. Feeling bad for it, my character kept him as he loots the party's mostly eaten bodies. As he touches the hamster's broken leg, the leg glows green and heals to near health. DM allowed me to multiclass to Druid for doing that. My character names his new friend Chompy
He unlocks the door, gets the item and returns to collect the money.
I was voted out of the game with the DM being the only one on my side since I was doing what my character would have done. Funny enough, he's used my character as a common bard song of legend and had my character write a book about it. So they'll never forget how to play in character.