We need more clues. Some of the clues you gave might suggest pokeweed
(Phytolacca americana). The palm tree thing and the narrow leaves
contraindicates pokeweed, but maybe it's a weird form of poke with narrow leaves
clustered at the top. Palm tree is a description that's in the eye of the
beholder. Cut open the stem. Is it hollow or pithy or what? Are the plants
connected to each other by the roots?