No Mutants Allowed

... 7 days?

Bismuth's half life is super long, far longer than the age of the universe. It's so long that it was assumed to be stable for the longest time until it was discovered that it was actually radioactive (just very, very weakly). Still no clue what's so special about it. Since he refuses to explain it due to me being mean to him, I guess we'll have to live with this lack of knowledge.

So 7 days was a little off?