SPOILERS Anyways, Yeah, Chara did that cause they wanted to set monsters free so they ate buttercups and poisoned themselfs and a few days later they died..the plan had failed and asriel took there soul and went to the surface, the humans thought asriel had killed chara, so they attacked him with everything they had, asriel had the power to destroy them all but he just smiled and walked off with chara, when they got back to the castle asriel died and his ashes spread across the golden flowers. Years and years 6 children had died, then one had fallen and there name was Frisk.

Yes there eating buttercups.