Conspire is a keyword ability that allows the spell cast to be copied if you tap two untapped creatures that share a color with that spell. Conspire was introduced in Shadowmoor. By 2010, it was considered a design failure. A keyword ability that creates a copy of a spell.
The second is a triggered ability that functions while the spell with conspire is on the stack. “Conspire” means “As an additional cost to cast this spell, you may tap two untapped creatures you control that each share a color with it” and “When you cast this spell, if its conspire cost was paid, copy it.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.) Target player mills four cards. Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it.