My new name doesn't have a middle name yet, so I'm accepting suggestions on what I could adopt that'd break as many systems as possible.

Obvious answers:
* null
* an emoji
* U+FFFD �
* half of a unicode surrogate pair
* EICAR
* some kind of prompt injection
* the entirety of DOOM, base64 encoded
* an illegal prime
* the source to decss
* 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

@foone why not something from the Under ConScript Unicode Registry?
That's Private Use Area, so that can break systems that are using the PUA characters in other ways
I'm partial to the sitelen pona block of the UCSUR since I'm a toki pona fan but there's a bunch of conlang scripts to pick from
@foone also, as a bonus, you can put meaning in the choice of what you say with it