Toilet and Pipe Problem

[ljowens405]

Noticed a fews weeks ago during the time when our area was under a freeze that the bowl in my basement toilet had completely dried up and the wall in back of the toilet looks like a pipe leaked all the way up to the ceiling of the basement bathroom. This bathroom is not on an exterior wall so I didn't think the pipe bursts especially since my main floor bathrooms were all ok. What could be causing this?

 

[Reach4]

How about the bowl dried out because nobody had used it in months?

The wall that shows formerly dripping water, that I presume has dried up, could be from when the toilet above overflowed.