Aah, nice idea. I imagine it would be frustrating if someone packed 6 of them, but in that case, it's just similar to Sundial.
I like it *thumbs up*
Many people are comparing this to phase shield / sundial, but there are some serious differences. If you throw this down with a PA, you are INVINCIBLE for atleast one turn, and requires no foresight. With sundials and phase shields, poison still brings damage and can be afflicted, as well as damaging spells. If you have 2 hp left and a phase shield out, Drain life, Poison, bla bla, can kill you. With this, they cannot. If you have 6in your hand, that's 6 turns of life essentially, not 6 turns of "I hope he doesn't have momentum"
Indeed, that's why they cost higher than 1/3 of a Phase Shield. However, this card also has a serious difference: Enemy will STILL hurt you until you have 1 HP left. With Phase Shield, no. And 1 HP left means less Electrum, and can get dangerous once you have no more of this.
The 6 in your hand can be frustrating, but filling your hand with these won't be fun either. They can screw almost any Fractal deck.
Other than that, this card can be stolen/destroyed as well.