Plant it to grow Dragon Gate. Punch the door to open or shut it. Anyone unlucky enough to be caught inside when it closes becomes dragon food.
Dragon Gate Seed price in Growtopia: sells for about 1 WL (median of 32 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: SGYAA, BKK1, JDFA, VENZSKI