The Fang of Critias

The Fang of Critias is also an 8/8 Legendary
Dragon creature named Legendary Dragon
Critias. As an additional cost to this spell, discard
an instant or sorcery named on a Fusion card you
own from outside the game that also mentions a
card named Legendary Dragon Critias. You may
reveal that Fusion card and put it onto the battlefield under your control. You can only cast
The Fang of Critias once per turn.
Limited 1