Need to bring back Undead Traits from 3.5

Back in the 3.5 days undead were scary. They were immune to a lot, and it made sense why they would be.

Immune to all mind affecting effects ( fear, sleep, confusion, charm, etc..). Immune to Critical hits. Immune to poison, disease, exhaustion, stun, paralyze

They were mindless legions of death and it was cool.

Low level undead like skeletons and zombies are jokes now.

We need to make them scary again.