The Turtles, Leo and others in “Unfinished Business”

Whoa.

So that's the...

...Mutagen that turned us all into what we are now.

Let's drink some!

What!? Why would you do that!?

'Cause if you mutate a mutant, you get a super mutant!

Or a pile of goo on the sidewalk.

Either way, it's an improvement.

Guys, this is huge. Whoever kidnapped those people are somehow connected to what happened to us 15 years ago.