The incantation spectral card is, to put it lightly, terrible. 4 random number cards are almost certainly not gonna help with whatever strategy one may be going for, not to mention the chance of destroying something good. I suggest making incantation give 4 of the same random number so that the player actually stands a chance of benefitting from the effect.
for reference: incantation destorys 1 random card in hand, then adds 4 random number cards to your deck