ChäoS;Child

Synopsis

After Kurusu is stabbed, Takuru infiltrates AH Tokyo General Hospital, hoping to find the creator of the sumo stickers. When he gets there, he, Onoe, and Itou are forced to hide in the basement to avoid being spotted. Inside the basement's autopsy room, they find a secret entrance that leads to an underground laboratory where terrible experiments were once conducted. Takuru thinks he's been here before...

(Source: Crunchyroll)