Sever the Bloodline

Oracle Text

Exile target creature and all other creatures with the same name as that creature.

Flashback 5BB (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Card Rulings

3/14/2017 Only creatures on the battlefield will be exiled. In other zones, they’re “creature cards,” not “creatures.”
3/14/2017 If the targeted creature is an illegal target by the time Sever the Bloodline resolves, it won’t resolve and none of its effects will happen. No creatures will be exiled.
3/14/2017 Unless a token is a copy of another creature or was explicitly given a name by the effect that created it, its name is the creature types it was given when it was created. For example, the Beast tokens created by Thragtusk and by Baloth Cage Trap are both named “Beast.”
3/14/2017 A double-faced creature only has the name of the face that’s up. For example, if Village Ironsmith is targeted by Sever the Bloodline, Ironfang wouldn’t be exiled.