I'm not talking about metamagic feats, I'm talking about a sorceror casting a spell at a higher level.
Specifically under Sorcerer class they have the ability called "heightened spell" which reads as such:
quote:
When you get spell slots of 2nd level and higher, you can fill those slots with stronger versions of lower-level spells. This increases the spell's level to match the spell slot. You must have a spell in your spell repertoire at the level you want to cast in order to heighten it to that level. Many spells have specific improvements when they are heightened to certain levels. The signature spells class feature lets you heighten certain spells freely.
So to cast Magic Missile at 3rd level, for example, you have to specifically use up a "spells known" slot at that higher level slot.
HOWEVER if you mark a spell as your signature spell then it doesn't take up that higher level "spells known" slot.