What is the first example you give them?

Like SCP-500, Panacea.

999, 131.

Well, Nobody likes SCP-999.

Everybody likes 999
999 is happiness
Except around 683, then it inadvertently causes mass destruction

SCP-999 is a complete menace. He shall be banished and sent to the sun.

And wait, How does a refrigerator make people psychotic?

SCP-683 is the Hard-to-destroy Reptile, which all research efforts on it have been bent to terminating it.
And SCP-999 is literally a yellow blob of lure happiness, it goes around Site 19 making everyone happy and lightening the mood
The reason it cause mass destruction is because when introduced to 683 for testing, SCP-683 took up some of its characteristics and released a high pitched, sonic laugh-screech which caused viewing researcher's eardrums to be burst and 683 breached containment

Bruh, That's SCP-682. SCP-683 is a refrigerator.

Oh f**k yeah that's my bad I don't know why I put 683
Sorry

It's fine.

Well... there's 005, 343, and 978.