Ok maybe not kill you but hurt you to say the least..

Your Nintendo 3DS system and software are not designed for use with any unauthorized device and/or any unauthorized software. Please note that the Nintendo warranties do not cover any defects to or defects caused by unauthorized devices, software, modifications and/or non-licensed accessories.

Furthermore such use may lead to injury to yourself or others and may cause performance issues and/or damage to your Nintendo 3DS system and related services. Nintendo (as well as Nintendo licensees or distributors) is not responsible for any damage or loss caused by the use of such devices, software, modifications or non-licensed accessories.

So modding my 3DS could cause it to explode….awesome!

Link