CTR and/or SAR and/or form 8300 and/or Fincen 105 when you actually spend it, either directly or they investigate and find you're the second link back. And if

CTR and/or SAR and/or form 8300 and/or Fincen 105 when you actually spend it, either directly or they investigate and find you're the second link back. And if you escape civil action by IRS, the fed or local government can simply take it as civil asset forfeiture without accusing you of wrongdoing. .gov really really hates big piles of printed currency and if they find out you have it the temptation for them to take it can become overwhelming to various entities that survive off of the taking.