CM Punk was asked at the Ohio Comic-Con in September last year if he would like to challenge Undertaker for "the streak" at Wrestlemania. The following quotes are directly from Punk:
"That Doesn't interest me… I like being in situations where you don't know who is going to win… Whoever wrestles in that I feel it's a foregone conclusion… There needs to be some drama and stuff."
This of course is relevant as it's believed he will indeed be the worker to challenge Undertaker at Wrestlemania 29 this year.
You can watch Punk's comments at the 27 minute mark at this link or embedded below: