You control Forests and/or green creatures that can tap to add ({2} magic symbol) ({U} magic symbol) ({G} magic symbol) ({G} magic symbol) .
Steps
Tap Forests and/or green creatures to add at least ({2} magic symbol) ({U} magic symbol) ({G} magic symbol) ({G} magic symbol) .
Pay ({2} magic symbol) ({G} magic symbol) and discard Colossal Skyturtle to activate its first activated ability, targeting Phantasmal Image.
In response, pay ({G} magic symbol) and tap Weaver of Harmony to activate it, copying Colossal Skyturtle's ability and choosing Colossal Skyturtle as the target.
Resolve all abilities, returning Phantasmal Image and Colossal Skyturtle to your hand.
Tap Patron of the Orochi to activate it, untapping all Forests and green creatures.
Pay ({1} magic symbol) ({U} magic symbol) to cast and resolve Phantasmal Image, having it enter as a copy of Patron of the Orochi.
Put the original Patron of the Orochi into the graveyard due to the legend rule.
Tap Forests and/or green creatures to add at least ({3} magic symbol) ({G} magic symbol) ({G} magic symbol) .
Pay ({2} magic symbol) ({G} magic symbol) and discard Colossal Skyturtle to activate its first activated ability, targeting Patron of the Orochi.
Pay ({G} magic symbol) and tap Weaver of Harmony to activate it, copying Colossal Skyturtle's ability and choosing Colossal Skyturtle as the target.
Resolve all abilities, returning Patron of the Orochi and Colossal Skyturtle to your hand.
Tap Phantasmal Image to activate it, untapping all Forests and green creatures.
Sacrifice Phantasmal Image and pay ({0} magic symbol) to cast Patron of the Orochi for its snake offering cost.