Bloody Friday lived up to its name. And Thursday was wall-to-wall carnage too.

The annual broadcast pruning of low-rated shows seemed to cut deeper than usual this year — at least emotionally — after networks went on an intense cancelation binge that included dumping several fan-favorite titles (full list below).

All told, 17 series were canceled in two days, with some verdicts that shocked even seasoned industry observers.

The biggest surprises were at ABC. Most assumed veteran procedural Castle would return for a ninth year, even as costar Stana Katic and Tamala Jones exited (which would have also reduced the show’s overall cost). Yet the network pulled the plug. Lucky for fans, producers shot two endings for the season in case they lost their battle to return.

The story was somewhat similar with Nashville, which oddsmakers expected to squeak by with another renewal (ABC even lined up new showrunners to take over the project for a fifth season). ABC axed it, though studio Lionsgate is shopping Nashville to other possible takers.

ABC also dumped freshman comedy The Muppets — a beloved franchise that was marketed heavily and double-downed on midway through the season by the network changing the show’s top writer-producer. Another surprise was the net’s decision to shed superhero content: Captain America spin-off Agent Carter was canceled, and its Agents of SHIELD spin-off pilot Marvel’s Most Wanted didn’t get picked up to series. Carter represents the first cancelation of a modern-day Marvel TV series. Netflix would seem like a natural outlet to pickup the show (when it comes to aquiring Marvel heroes, Netflix is like a TV company version of The Collector), sources say such a rescue isn’t happening.

All those cancellations could have been partly impacted by ABC coming under new executive management this year. Longtime entertainment chief Paul Lee stepped down in February and was replaced by the network’s drama chief, Channing Dungey.

In another superhero rebuke, CBS booted Supergirl to The CW. From the moment Supergirl was announced, fans wondered why the show wasn’t on The CW along with other Greg Berlanti-produced DC Comics titles like The Flash and Arrow, and questioned whether its brand fit CBS, but the network defended the move. Next season we’ll see if Kara’s new home will indeed make a better fit — and if any of the show’s expected budget reduction will show up on screen.

On Fox, Rob Lowe’s criticallly well-regarded freshman comedy The Grinder was axed, along with John Stamos’ rather less regarded companion series Grandfathered. Neo-Frankenstein drama Second Chance won’t get a second chance either.

Over at NBC, the network’s losses were contained to, how shall we say, lower-profile shows (some TV fans noted on Twitter they had never heard of some of NBC’s canceled titles). Several were only launched in midseason and failed to gain traction, like the medical drama Heartbeat and the sitcom Crowded.

The cancelations also may reflect that sagging broadcast ratings have hit a level where it’s no longer just about sniping the weakest shows in the herd, but that the performance of some titles are so low — and their budgets still relatively high — that certain programs are just no longer viable. In past years, executives could figure, “let’s eliminate our weakest programs and try something new”; now, the situation can be more like, “the cost-benefit math of these shows are below-the-line unacceptable for our business model.” Like Agent Carter — the period action drama averaged the same adult demo rating (a 1.4 among adults 18-49) as ABC’s Real O’Neals and Dr. Ken, yet the far-cheaper comedies scored renewals.

Sadly, there’s more bloodshed to come. CBS has yet to lower the boom on any of its freshman titles other than CSI: Cyber, while two NBC bubble shows (The Mysteries of Laura and The Carmichael Show) nervously await a verdict.

Here is a list of all the shows axed in the past two days:

Agent Carter (ABC, 2 seasons)

Bordertown (Fox, 1 season)

Castle (ABC, 8 seasons)

Containment (CW, 1 season)

Crowded (NBC, 1 season)

CSI: Cyber (CBS, 2 seasons)

The Family (ABC, 1 season)

Galavant (ABC, 2 seasons)

Game of Silence (NBC, 1 season)

Grandfathered (Fox, 1 season)

The Grinder (Fox, 1 season)

Heartbeat (NBC, 1 season)

The Muppets (ABC, 1 season)

Nashville (ABC, 4 seasons)

Second Chance (Fox, 1 season)

Telenovela (NBC, 1 season)

Undateable (NBC, 3 seasons)