Why can't it be something like...well it can't be an exclamation point because imaginary numbers stole that >-<!
Maybe a swirl

!!!
Well...maybe not...I guess the loops are better since it can keep going..In fact maybe it's not an 8 on its side..maybe it's a cousin of the 8..or perhaps they are entirely unrelated...
Besides Infinity and beyond should be ...I don't know how you do infitinity symbols >-<! darn it well just add a + sign on that. And there.