Gleipnir

グレイプニル

Shuichi Kagaya, a quiet high schooler, can transform into a giant mascot-like creature—a plush dog suit with a zipper on the back. When classmate Claire Aoki discovers his power after he rescues her from a fire, she blackmails him into helping her hunt down her sister Elena, who murdered their parents. Claire fights by climbing inside Shuichi's monster form and piloting it from within. Their search leads them to an alien hiding in a vending machine that trades golden coins for supernatural abilities, and to other coin-holders competing to gather the scattered set.