Ruth Negga, Clark Gregg

[Warning: This story contains spoilers from Tuesday's Marvel's Agents of S.H.I.E.L.D. Read at your own risk!]

Agent Coulson is the key to unlocking Stage 3 — whatever that means.

On Marvel's Agents of S.H.I.E.L.D.'s midseason finale, the team was thwarted by Centipede, who have so far been one step ahead of them all season thanks to The Clairvoyant — whoever that is.

See, Centipede's own soldiers have been essentially breaking down after every mission, unable to sustain their power without new injections. But when they see video -- oh hey, they created that eye camera that plagued Akela Amador (Pascale Armand) a few episodes back! -- of S.H.I.E.L.D. operative and former Centipede test subject Mike (J. August Richards) still retaining his powers without any recent injections, Centipede holds his son hostage to make a trade, presumably for Mike. That's because he is seemingly the key to unlocking the next stage in their Centipede super-soldier trials.

Agents of S.H.I.E.L.D.: Did Ward and Melinda May really hook up?

However, there's a catch. It turns out they don't want Mike after all. He will only get his son back if he hands over ... Agent Coulson (Clark Gregg). Why? "We want you to tell us about the day after you died," Raina (Ruth Negga), aka the girl in the flower dress, tells Coulson as their helicopter flies off after seemingly killing Mike and shooting Ward (Brett Dalton). Does this mean they're trying to use Coulson's Life Model Decoy technology to stabilize the Centipede serum? Because seriously, he's a Life Model Decoy, right?

We'll find out for sure — possibly — when Marvel's Agents of S.H.I.E.L.D. returns on Tuesday, Jan. 7 at 8/7c on ABC. What did you think of the midseason finale? Hit the comments!