Concept
This is basically a voltron deck centred around the card Cosmo.
As long as Magik is in hero form, the top card of her deck is always flipped, so forecasting the correct card type is guaranteed, thus Cosmo won't suffer any consequential damage when thwarting or attacking. We abuse this fact by buffing Cosmo and readying him repeatedly per turn.
In order to maximize your hand size and for the purpose of recovery, you want to regularly flip between alter ego and hero form. While Cosmo can thwart if need be (up to 3 per use) his main role is dealing damage (up to 5 per use). With several Command Team and Get Ready cards on the table, he will be wreaking havoc in no time. With Sidekick you can further increase the usefulness of #Collossus.
Magik herself can be either used for defending, attacking or even thwarting, whatever fits best in the current situation.
Mulligan
Your main goal is to retrieve either Cosmo or one of the three #Suit Up cards asap. Chances of getting at least one of these 4 cards on your first hand are 49%, respectively 78% in case of a full mulligan.
Another key card to look for is The Sorcerer Supreme.
Goals
The following cards should be attached to Cosmo:
[Honorary X-Men](/card/33035) (should be your first priority since it is required for [Danger Room Training](/card/33015))
[Danger Room Training](/card/33015)
[Inspired](/card/01074)
[Laser Blaster](/card/17019)
[Sidearm](/card/23035)
Tips and Tricks
Besides [Honorary X-Men](/card/33035), the order doesn't really matter, so just grab whatever upgrade you can get your hands on. You can also use the #Suit Up cards to merely collect missing upgrades, since no one forces you to pick up an ally as well, (although you normally wanna do this, if an ally is still available). And even if you grab both an ally and an upgrade, you can still use the upgrade for another ally.
[Spiritual Meditation](/card/15019) gives you another option for card advantage and grabbing the flipped top card of your deck, but you should be considerate about it. Sometimes it can be better to resist the temptation by not playing [Spiritual Meditation](/card/15019) and saving the top card of the deck for the next turn.
[Pixie](/card/36017) is nice for chump blocking as well as calling #Collossus at the same time, so if you have enough resources, don't call #Collossus directly but let [Pixie](/card/36017) do the job for you
If you flip from alter ego to hero form, picking [Scrying](/card/45036) is a perfect choice to further increase your hand size
Main advantages of this deck
It just takes a few turns to set up [Cosmo](/card/17020) properly, so you can hit the villain hard early on
Even if your hero is constantly stunned or confused, it doesn't make that much of a difference (compared to the likes of [Quicksilver](/card/14001a))
The deck is both strong in terms of thwarting and attacking
Fairly low cost curve
Knowing the top card of the player deck just opens up so many possibilities ...