And the winner is: Griptide, of course. Its the card that will take your opponents Monstrosity play off the board.
1. The creatures.
white
creature cavalry pegasus 2/1/1 Flying (C)
creature decorated griffin 5/2/3 Flying (U) activation prevents damage
devotion creature evangel of heliod 6/1/3 (U)
creature wingsteed rider 3/2/2 Flying and Heroic (C)
blue
creature breaching hippocamp 4/3/2 Flash (C)
creature horizon scholar 6/4/4 Flying and Scry 2 (U)
creature omenspeaker 2/1/3 Scry 2 (C)
creature prescient chimera 5/3/4 Scry 1 for I+S (C)
creature vaporkin 2/2/1 Flying and only blocks Flying (C)
black
creature blood-toll harpy 3/2/1 Flying ETB opp -1 life (C)
devotion creature gray merchant of ephodel 5/2/4 (C)
devotion creature mogi's marauder 3/2/2 (U)
creature insatiable harpy 4/2/2 Flying, Lifelink (U)
red
devotion creature fanatic of mogis 4/4/2 (U)
creature minotaur skullcleaver 3/2/2 Haste (C)
green
devotion creature nylea's disciple 4/3/3 (C)
creature sedge scorpion 1/1/1 deathtouch (C)
2. Artifacts
equipment 2+2 Flying and Haste (C)
equipment 1+1 Scry 1 (U)
3. Control and removal
white
instant divine verdict 3 destroy attacking or blocking creature (C)
instant last breath 2 exile power 2 or less creature opp plus 4 life (C)
instant ray of dissolution 3 destroy enchantment gain 3 life (C)
blue
instant annul 1 counter artifact or enchantment (C)
instant griptide 4 creature on top of owner's library (C)
instant dissolve 3 counterspell, scry 1 (U)
sorcery thassa's bounty 6 draw three cards mill 3 (C)
instant stymied hopes 1 counterspell pay 1 scry 1 (C)
instant voyage's end 2 creature to owner's hand scry 1 (C)
black
sorcery read the bones 3 scry 2 draw 2 pay 2 life (C)
instant pharika's cure 2 2 damage to creature gain 2 life (C)
e-a viper's kiss 1 -1/-1 to creature disable abilities (C)
red
instant lightning strike 2 3 damage C+P (C)
instant magma jet 2 2 damage C+P scry 2 (U)
sorcery portent of betrayal 4 'treason' (C)
sorcery rage of purphoros 5 4 damage to creature scry 1 (C)
instant spark jolt 1 1 damage C+P scry 1 (C)
green
instant artisan's sorrow 4 'naturalize' scry 2 (U)
instant defend the hearth 2 crature or enchantment from top five cards (C)
sorcery fade into antiquity 3 'exile naturalize' (C)
instant shredding winds 3 7 damage to flyer (C)
artifact
flamecast wheel 1+5 3 damage to creature (U)
4. Heroic enablers (in addition to the ordeals)
white
instant battlewise valor 2 +2/+2 EOT scry 1 (C)
e-a chosen by heliod 2 +0/+2 draw 1 (C)
instant dauntless onslaught 3 [two creatures] +2/+2 EOT (U)
blue
instant triton tactics 1 [two creatures] EOT blocker and tapper (U)
black
instant cutthroat maneuver 4 [two creatures] +1/+1 and lifelink (U)
e-a scourgemark 2 ETB draw 1 +1/+0 to creature (C)
red
instant coordinated assault 1 [two creatures] EOT +1/+0 first strike (U)
e-a dragon mantle 1 ETB draw 1 1 red mana for +1/+0 pumper (C)
e-a messenger's speed 1 trample and haste (C)
instant titan's strength 1 +3/+1 EOT scry 1 (C)
green
e-a feral invocation 3 flash +2/+2 (C)
instant savage surge 2 EOT +2/+2 untap it (C)
instant warriors' lesson 1 [two creatures] draw card when deals combat to player (U)
5. Heroic
white
favored hoplite 1/1/2 +1/+1 counter prevent EOT damage (U)
phalanx leader 2/1/1 +1/+1 counter on each creature (U)
blue
triton fortune hunter 3/2/2 draw 1 (U)
wavecrash triton 3/1/4 tap opp creature (C)
red
akroan crusader 1/1/1 place 1/1 token with haste (C)
arena athlete 2/2/1 opp creature can't block (U)
green
centaur battlemaster 5/3/3 three +1/+1 counters (U)
staunch-hearted warrior 4/2/2 two +1/+1 counters (C)
