Hell is cold: Captain Cold and the Suicide Squad
Okay, so it's common knowledge that Flash's rogues were well represented among the Suicide Squad by Digger Harkness aka Captain Boomerang. However, old Boomerbutt wasn't the only one of Flash's perennial foes to 'volunteer' for this ragtag bunch. Leonard Snart, who you may know better as the cool, cruel Captain Cold, pitched in once or twice as well.
Two pages out of twenty-two from Suicide Squad #17 and #18 each. Credits for these pages go to John Ostrander's mighty pen and Luke McDonnell's thousand words. Scans are not mine.
Let me give you a little context: the Jihad, nemeseseseses of the Suicide Squad come back for revenge after their defeat earlier in the mag's pages. They're terrorists from Qurac and they've got it out for Manhattan. This happens in issue #17.
Then, in issue #18, Captain Cold faces Agni.
Agni gets put on ice. Unfortunately, the good Captain doesn't return to the Suicide Squad after these issues (which also includes the unposted #16).