Yo dawg, I heard you like +1/+1 counters...
This deck is too slow for a real tournament, but among my friends who are more casual it's somewhat infamous and kinda mean. This deck took months to perfect and is the first deck I can really call my own.
Experiment One and Slitherhead are your bodies. Personally I find it difficult to get Experiment One to two +1/+1 counters early enough in the game for it to matter, but whether you do or not, he's just a 1/1 body meant to stall while you hit that sweet 4 mana spot and get the star players of this deck out. Slitherhead too is a body meant to be steamrolled-- he's much more helpful in the graveyard as he's a valuable source of +1/+1 counters later in the game.
The star players of this deck are Master Biomancer and Corpsejack Menace. They can fight for you if you need them to, but ideally you should treat them as enchantments. Your fighters are Vampire Nighthawk and Elusive Krasis, and everything else in the deck is built around making those fighters as ridiculously huge as possible.
Forced Adaptation adds a +1/+1 counter to a creature at the beginning of your upkeep. You could put it on one of your attackers, or you could put it onto a Master Biomancer to make your as-of-yet-uncast creatures bigger and bigger each turn. And anything the Biomancer does, Corpsejack doubles, so even with just one Corpsejack and one Biomancer, creatures are coming in with four +1/+1 counters. With two Forced Adapations, two Corpsejacks, or two Biomancers (or two or more of all three) it gets ridiculously stupid. All out of Forced Adaptations? Use a Bioshift to move those +1/+1 counters onto a more suitable attacker, but make sure you have at least one Corpsejack out when you do! Because then those four +1/+1 on your Master Biomancer just doubled to eight +1/+1 counters on your Vampire Nighthawk (and if you had two Corpsejacks out, your Nighthawk is now an 18/19)! Keep track of any Slitherheads chilling in your graveyard too, since with just one Corpsejack Menace you get two completely free +1/+1 counters to put wherever you need them.
There are countless other slight variations on doubling, quadrupling or octupling +1/+1 counters with Corpsejack so I won't list them all here. Suffice to say, if you're placing +1/+1 counters, moving +1/+1 counters, or just evolving the old fashioned way with Elusive Krasis, and there's a Corpsejack out, double them. If there's two, quadruple them. If there's three, multiply them by eight. And if you're lucky enough to have all four of them out, multiply them by a whopping 16.
Vorel of the Hull Clade is a very recent addition that I haven't yet fully tested. He does a similar job as Corpsejack, but I get to choose when to double counters and I can do it several times a game. He merely replaced two Leyline Phantoms, which I didn't really need and rarely played.
