If you happen to drink spoiled half and half you're gonna get sick and probably vomit or at least have a very bad stomach ache for awhile.
Drinking spoiled half and half will also make you have severe stomach cramps and possibly diarrhea and nausea so I would avoid drinking any spoiled or expired half and half.
Any half and half or milk that has gone bad will make you sick and then you'll wish you hadn't drank the spoiled milk or spoiled half and half.
You likely will be okay and not die from drinking spoiled half and half but it will make you sick and it will taste awful as well.
The smell of the half and half that is spoiled would also be bad.