Don Draper: The Undead Years? Probably not going to happen, but maybe it should. Ratings are in for Sunday’s debut of AMC’s new zombie drama The Walking Dead, and they were, well, monstrous. Nielsen says 5.3 million people watched the 90-minute bow at 10 p.m. on Halloween, giving AMC its biggest audience ever for an original series, and far surpassing the numbers for network staples such as Mad Men and Breaking Bad. (The network’s all-time draw remains the mini-series Broken Trail, which premiered to nearly 10 million viewers back in 2006.) Add in same-night repeats of Dead, and the show’s premiere audience rises to just over 8 million viewers. What’s more, Dead was particularly big with viewers under 50: Around 3.6 million in that demo watched, making the show the biggest cable-series premiere among the young folks this year. So does this mean Dead will be back for a second season?

Most likely, yes. Dead more than doubled the audience of past AMC series premieres, and the demos are simply stunning (particularly for a channel that has tended to skew a bit older). That said, AMC may wait to make sure viewers stick around in coming weeks for future zombie adventures. After all, earlier this year the network’s Rubicon bowed to a then-record 2 million viewers; by the time the show wrapped its first season last month, it was down to barely 1 million. That said, even if Dead loses half of its audience, it’ll still be in the same league as other successful AMC series. As AMC president Charlie Collier put it in the network’s press release touting the show’s ratings, “It’s a good day to be dead.”