The final benefit of the War Caster feat says (PHB, p. 170):
The spell […] must target only one creature.
If my character is level 5+, does a spell like eldritch blast still meet this condition as long as all of the beams are directed at a single target?
Basically, does the "must" just restrict what targets I can choose for the spell? Or does it restrict the selection of the spell itself based on what I can target?