my bad gem ideas

Imprisoning frost wall of imprisonment:

Traps enemies with you in a circle of ice so they can't escape.

Summon bug

Summons a bipedal insectoid that has augmented flicker strike. Upon killing a living target with a melee attack, creates a zombie. Zombies created this way which are killed resummons another bug. If the zombies are not killed within 30 seconds of being spawned, another bug pop out of the created zombie corpse. Limit 1 bug.