It's still going to be almost impossible as you have tough cards left...
Untap, Upkeep, Time Counter on Mycoderm.
Play Plains
Play Voidstone Gargoyle, naming Pongify
Done.
Spidey: 27
Hand: 5
Battlefield:
(T) Forest
(T) Swamp
(T) Island
(T) Plains
(U) Mt
(U) Essence Warden (1/1; Whenever another creature ETB, I gain 1 life)
(T) Darkheart Sliver (3/3 from Sinw; All Slivers have "Sac this permanent: You gain 3 life")
(U) Sinew Sliver (2/2 from itself; All Sliver creatures gets +1/+1; Sac this permanent: You gain 3 life from Darkheart)
(S) Primal Plasm (2/2; Flying)
Graveyard: Keldon Marauders, Simian Spirit Guide, Frozen AEther, Aquamorph Entity, Wistful Thinking, Poultice Sliver
Exile:
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BigBlue: 20
Hand: 6
Battlefield:
(T) Island
(TT) Swamp
(TT) Plains
(U) Forest
(U) Facedown Creature (2/2)
(U) Pallid Mycoderm (2/4; At Begin of Upkeep add a TC; Remove 3 TC: put a 1/1 Saproling in Play; Sac a Saproling: All fungi and saprolings I control get +1/+1 until eot) (fungus) (2 Time Counters)
(S) Voidstone Gargoyle (3/3; Flying; When ~ CiP choose the name of a card. Cards with that name may not be played, have abilities activated in play or out of play) (Named Pongify)
Graveyard: Wistful Thinking, Simian Spirit Guide, Battering Sliver, Healing Leaves, Vampiric Link, Treacherous Urge
Exile: