Echo Chamber

Echo Chamber is a passive item added in The Binding of Isaac: Repentance.

Effects

 * When using a pill, card, or rune, Echo Chamber activates one of every pill type, card type, and rune type that has been previously used since obtaining Echo Chamber.

Synergies

 * Can be used to spawn infinite cards.
 * Allows for infinite duplication of items and consumables.
 * + / Vurp Pill + : The ? Card effect can be used in conjunction with R Key without consuming it, allowing the player to in theory (with the help of ) obtain completion marks for multiple routes and characters in a single run.
 * Using the R key does not reset the pill pool, as such they stay the same in Echo Chamber too.
 * Victory laps do reset the pill pool, all pills inside of echo chamber use their new effect.
 * Vurp Pill: Can be used to spawn infinite pills.
 * ,, or : All activated pills are converted to their good counterparts, including pills taken prior to picking up , , or.
 * Taking benign pills (e.g. puberty) will give black hearts or damage ups for each of the pills that are activated. Caution should be exercised when using this synergy, since all previously taken pills will be converted to their bad counterparts, and one stat down can ruin the synergy.
 * Every activated tarot card will be given a bonus effect.

Trivia

 * This is possibly a reference to the card Eye of the Storm from Magic: the Gathering, as the item resembles the art of the card and both result in previous effects being reused when a new one is activated.