While we had designed individual cards that made temporary tokens, myriad was the first named mechanic to make use of this design technology
It gets a +1/+1 counter on it whenever you cast a creature spell, and then makes each creature spell you have cost one mana less to cast for each +1/+1 counter on it
If you don't care about the initiative and aren't overlapping with the party mechanic, you probably don't want to run this just for the explore
It can ruin the life of engine-builder players (+1/+1 counters, planeswalkers, tokens, you name it)
Such trickery includes temporarily gaining control of permanents (Threaten effects), preventing creatures from blocking ("Panic"), and changing the targets of spells, though some cards in this category are truly unique
With Flying and a 5/5 life counter, Shivan Dragon is able to wreak havoc on the opponents battlefield and, if left unchecked, ends matches in short order