Zaberoth: Mechanics

Dementia: Rather than life loss, damage this deals to a player causes that player to exile that many cards from the top of his or her library. Used on 21 cards: Rage Effigy, Skulking Dreambane, Windswept Wretch, Dead Lake Wraith, Valnoth Dreambane, Terror Elemental, Two-Headed Abomination, Lorn Shadow, Twisted Poppet, Stalking Slasher, Ghast Spark, Sanity Slayer, Ascendant Aberration, Nightmare Serpent, Null Lightning, Grudgeon Shambler, Overlord of Despair, Voidspawn, Dead Lake Unravelers, Tormentor Phantasm, Hungering Monstrosity

Nightmare tribe's mechanic. In a manner similar to infect, damage to players is in the form of super-milling (exiling cards from the top of the library).

This is not a replacement effect; it directly modifies the effects of damage. The damage is dealt in the "form" of exiling cards; effects like lifelink will function as normal.
If a permanent gains two damage-modifying effects (e.g. infect and dementia), the damage modification that is applied is determined by timestamp order. For example, if a creature with dementia later gains infect, it will deal damage to players in the form of poison counters, and vice versa.

Psyche: As you draw a card, you may exile it and put a psyche counter on this. Used on 24 cards: Cerebral Horror, Feral Huntpack, Cunning Rootwalla, Runic Automaton, Vaashin Cutthroat, Mossheart Nourisher, Chords of Burning, Fireheart Sigil, Rune-Etched Vestments, Itzent Stormseeker, Ardent Champion, Malach of Retribution, Errasi Drakeling, Lornwind Apparition, Mind Meddling, Rixian Infiltrator, Entrancing Specter, Eltis Empath, Keen Guardian, Order of Tibern, Kolonar's Elite, Valnoth Stormfoot, Supreme Dispeller, Makar Lancer

Turns drawn cards into psyche counters, which do various things. IMPORTANT: You now see the card you draw before you decide whether to exile it.

The full rules text of psyche is "As you draw a card, you may exile that card from your hand. If you do, put a psyche counter on this permanent."
The drawn card[s] must be kept clearly separate from the player’s hand until a decision is made whether to use psyche. A drawn card that is placed into a player’s hand cannot be exiled for a psyche counter.
Players cannot respond to psyche (e.g. by casting the card being drawn, or somehow forcing that card to be discarded); as the draw happens, the decision is made whether to exile the card.
If a player controls multiple permanents with psyche, each drawn card can only be exiled for one of those permanents’ abilities. (That is, you only get one psyche counter per drawn card.)
Cards that are put into a player’s hand through methods other than drawing will not trigger psyche.

In card text or details pages, write the mechanic's code name (playtest name) between square brackets, like "[Crittercast]", "[Bushido 1]" or "[Delay 4 {2}{R}{R}]". It will be expanded to the mechanic's name plus reminder text, such as "Suspend 4 – {2} {r} {r} . (Rather than cast this spell from your hand,...)"
To expand a mechanic's name but not its reminder text, include parentheses at the end of the square brackets: "[Crittercast()]", "[Delay 9 {R}()]".