What is the equivalent of Skull Trap or Glyph of Warding in Savage Worlds?

I am converting Return to the Keep on the Borderlands into a Savage Worlds test. Mainly because that adventure is very localized and has all the basic role-playing elements (Hack and Slash, Intrigue, Mystery, Diplomacy etc.) which makes is a good testing ground for my players and I to feel out the system as a possibility of a full move from 5E.

As I was converting some of the encounters and monsters I stumbled across a place where there were what amounted to what would be considered in 5E as a Glyph or in an old Dragon article a Skull Trap.

Basically, Skull Trap was a 2nd or 3rd level Necromantic spell that allowed the caster to imbue an intact skull to be more or less like a landmine. If disturbed it would explode and all in the radius would take damage.

Since Savage Worlds leans mostly on Power Points and they regenerate insanely fast I have seen that they tend to essentially invest the Power Points and they don’t regain them until the trap is triggered.

Are there other ways to adjudicate this? I realize there are a number of settings out there with varying magic systems and I have seen the Savage Vancian versions but they don’t seem to really work for me.

Essentially, is there a way for a power to be used to create a trap that lasts indefinitely without investment of Power Points and if so what are the balance issues of allowing this? I had thought to allow it but increase the casting time significantly for long standing effects.