Plant it to grow Cosmic Rain. This is what the call "hard radiation". That of course means it's solid so you can't jump up through it, you can however drop down, since it's moving down!
Cosmic Rain Seed price in Growtopia: sells for about 30 WL (median of 13 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: JTCL