Trick or treat? This month was all about the latter. With Katy Perry's 'Prism,' new Lady Gaga singles and a surprise Taylor Swift song all dropping in the last four weeks, we've developed a serious case of the sweet tooth. Arcade Fire's James Murphy-assisted album also arrived, while newcomers like MellowHigh and Tori Kelly earned our attention. Spin the best songs of the month, including tunes from Pusha T, Diane Birch and Active Child. What a rockin' October.