Gamma Attack!

Gamma Attack! was a two part event that ran in 2016. Part one ran from March 4 to March 11, part two from March 11 to March 18. Three primary heroes were pre-selected and equipped with special training actions ranging from two hours in length to eight hours. Once accumulated, the hero could go into battle with the current boss, depleting some of his HP and being rewarded with gamma blockers, used to purchase rewards.

Gamma Attack, Pt. 1
Heroes: Iron Man, Wasp, Loki

"The Leader threatens to unleash Gamma radiation across the whole planet! He plans to start his reign of terror by taking over the Academy and has enlisted the mind-controlled A-Bomb and Red hulk against the Avengers!" The payout per battle is 5 Gamma Blockers. There is also the option of spending shards to buy Gamma Labs for a daily blocker payout, where you can send Spider-Woman and/or Vision to boost production.

Gamma Attack, Pt. 2
Heroes: Wasp, Black Widow, Falcon, A-Bomb

The battle for Avengers Academy continues! With A-Bomb out of the equation, the Leader sends forth his second prize fighter: the Red Hulk. It's revealed that the Leader hasn't just promised him the Hulk, but is threatening to use a cranial implant in Red Hulk's skull to implode his brain if he doesn't do exactly as commanded. The regular payout per battle is 11 Gamma Blockers. (Additionally, if you managed previously to recruit A-Bomb he has a special 12-hour action - requiring no training - that rewards a single additional Gamma Blocker.) There is also the option of spending shards to buy Gamma Labs for a daily blocker payout, where you can send Spider-Woman, War Machine and/or Vision to boost production.

Quest Chain
Red Rage, Pt. 1
 * Train your heroes and get ready to fight!
 * Battle Red Hulk!

0-20 Red Gamma Blockers Wasp: Plan Some Attacks (2 hrs), Avengers Dorm Black Widow: Stay On Target (4 hrs), The Blasting Range Falcon: Punch Out! (8 hrs), Avengers Dorm A-Bomb: Roll to Battle (12 hrs), Quad

Step Right Up, Pt. 2
 * Get 50 Red Gamma Blockers
 * Place the Gamma Cannon!

20-50 Red Gamma Blockers Wasp: Check Secret Weapons (2 hrs), Stark Tower Black Widow: Search For Weakness (4 hrs), Quad Falcon: Practise Agility (8 hrs), Quad A-Bomb: Roll to Battle (12 hrs), Quad

Step Right Up, Pt. 3
 * Get 90 Red Gamma Blockers
 * Place the Prototype Hulkbuster!

50-90 Red Gamma Blockers Wasp: Blast Bullseyes! (2 hrs), The Blasting Range Black Widow: Hack Leader's Tech (4 hrs), Stark Tower Falcon: Find The Fight Club (8 hrs), The Timeless Archives A-Bomb: Roll to Battle (12 hrs), Quad

Hulk Knock Life, Pt. 1
 * Get 150 Red Gamma Blockers

90-150 Red Gamma Blockers Wasp: Bob And Weave (2 hrs), Quad Black Widow: Test Your Armor (4 hrs), Stark Tower Falcon: Read To Succeed (8 hrs), The Timeless Archives A-Bomb: Roll to Battle (12 hrs), Quad