Iridescent Drake

Flying
When this creature enters, put target Aura card from a graveyard onto the battlefield under your control attached to this creature.

Colossification

Enchant creature
When this Aura enters, tap enchanted creature.
Enchanted creature gets +20/+20.

Followed Footsteps

Enchant creature
At the beginning of your upkeep, create a token that's a copy of enchanted creature.

Serum Powder

{T}: Add {C}.
Any time you could mulligan and this card is in your hand, you may exile all the cards from your hand, then draw that many cards. (You can do this in addition to taking mulligans.)

Endless Evil

Enchant creature you control
At the beginning of your upkeep, create a token that's a copy of enchanted creature, except the token is 1/1.
When enchanted creature dies, if that creature was a Horror, return this card to its owner's hand.

Island

Mirror Mockery

Enchant creature
Whenever enchanted creature attacks, you may create a token that's a copy of that creature. Exile that token at end of combat.

Ghastly Mimicry

Enchant creature
At the beginning of your upkeep, create a token that's a copy of enchanted creature, except it's a Spirit in addition to its other types.
If Ghastly Mimicry would be put into a graveyard from anywhere, exile it instead.

Mirrorhall Mimic

You may have this creature enter as a copy of any creature on the battlefield, except it's a Spirit in addition to its other types.
Disturb {3}{U}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Mirrorhall Mimic // Ghastly Mimicry

Academy Researchers

When this creature enters, you may put an Aura card from your hand onto the battlefield attached to this creature.

Shape of the Wiitigo

Enchant creature
When this Aura enters, put six +1/+1 counters on enchanted creature.
At the beginning of your upkeep, put a +1/+1 counter on enchanted creature if it attacked or blocked since your last upkeep. Otherwise, remove a +1/+1 counter from it.

Gigantiform

Kicker {4}
Enchant creature
Enchanted creature has base power and toughness 8/8 and has trample.
When this Aura enters, if it was kicked, you may search your library for a card named Gigantiform, put it onto the battlefield, then shuffle.