Spellblast (Sp)
This invocation (Lesser; 4th; Eldritch Essence), learned at 3rd level, allows you to place an arcane spell that affects an area upon your eldritch blast. If the eldritch blast hits its target, the spell's area is centered on any corner of the target's space, even if the spell could normally be centered only on the caster. If the eldritch blast misses its target, the spell is lost with no effect.
It takes a full-round action to cast the spell and fire the eldritch blast. Only an area spell with a casting time no greater than 1 standard action can be placed upon your eldritch blast.
Only the first target of your eldritch blast is affected by the spell (for example, an eldritch chain spellblast centers the spell on the initial target, not on any of the secondary targets). If your eldritch blast doesn't specify a target, you can't apply this invocation to the blast.
Treat spellblast as a spell whose level is equal to the area spell placed upon the eldritch blast (minimum 4th level).