Asphyxiate

choose a creature in sight. You wrap your hands around your own throat and choke yourself which causes the target to begin choking as well. You both make a constitution saving throw with your spell save DC at the beginning of your turn or take 1d8 force damage on a miss. If you succeed the Constitution save, take 1d4 force damage, if you fail, take 3d4 force damage and go unconscious. The spell ends when either you or the target go unconscious. 

This spell has no effect on amphibious or aquatic creatures or undead.