Aya has a switch on her head. Holding Z pulls the switch, changing her eye color.
Slithering / Zuruzuru (ずるずる)
Aya has something pink slithering behind her as she walks.
Aya carries a scythe, allowing her to kill NPCs.
Dune / Sand Hill (すなやま)
Aya's body wrapped in a dune. Holding Z makes her tuck her head inside it and return to the nexus.
Aya has a wheel attached to her body, splitting her in half. Holding Z makes her body split and deploys the wheel, doubling her speed. Holding Z again makes her retract the wheel into her body.
Aya wears a black mask with an eye on it. Holding Z changes the eye's color.
Aya carries a rifle on her back, allowing her to kill NPCs.
Half of Aya's body is missing, allowing her to pass through narrow entrances. Holding Z switches the side of her body that is visible.
Rocks / Stones (いしころ)
Aya turns into a couple of rocks, making her unable to move but hiding her from chasers.
Aya has three legs.
Aya has a manhole cover on her head. Holding Z makes her dive underground, hiding her from chases but not making her invulnerable; the effect also allows her to pass through low entrances when underground.
ASCII Art (アスキーアート)
Aya is drawn in ASCII art. Holding Z makes the upper part of the string displace, Aya fixing it afterwards.
Aya is (seemingly harmlessly) sliced horizontally into 5 parts, each moving around as she walks. Holding Z makes her drop the pieces down on top of each other.
Bed Hair (てんねんパーマ)
Aya's hair becomes messy. Holding Z makes her try to straighten it, but it goes back to its previous form.
These were Aya's effects before version 0.006. In version 0.004, the effects lacked button actions and the Blue effect looked different. In version 0.005a, there was an effect action button in the Items menu. All of Aya's sprites were missing eyes in these versions, but there was a hidden patch in the GameOver folder giving her sprites eyes.
Aya becomes a red and black-cloaked person with an explosion/flower(?) for a head, making her able to kill NPCs. Using the action item shrinks and grows the explosion/flowers.
Aya becomes a cat-eared brunette with orange clothes. Using the action item makes her dance.
Aya becomes a "human lightbulb". Using the action item toggles the "light" on or off.
Aya becomes a walking green onion, letting her walk into some secret areas.
Aya becomes a green blob. Using the action item lights up the red eyes(?).
0.004: Aya becomes a person that has spiky blue hair and blue clothes.
0.005a: Aya becomes a blue popsicle, making her immobile.
Aya's head becomes a fishbowl with fish inside. Using the action item rots away the fish and sends her to the nexus.
Aya looks like the doll (named "Rusia" according to the game files) from the Circus in the Cursed Maze. using the action item makes it snow, and the effect can also stop chasers in place.
Aya gets purple hair and wears a purple trench coat and fedora. She walks backwards, but using the action item switches her movement style from backwards to forwards.
Aya wears pink clothes and has pink hair with a ponytail. Using the action item makes her do some hand motions.
Aya becomes a person with a mask. Using the action item summons rain.