"What do you think happens if you overdose with iodine?"
1) You could get the feeling of drinking several expressos-- very jazzed.
2) Your body will eliminate the excess via kidneys.
3) You could feel really crummy.... someone has posted his experience of doing several hundred mg of Iodine (I think it was 400), it would kick off detox symptoms most probably.
4) The upper limit of safely taking Iodine is quite high...I think a gram or two, someone else can chime in if I'm wrong.