Mega Gnar Boudler should be terrain

When Mega Gnar throws out his boulder it should appear as terrain so that Gnar can chain his ultimate with the boulder. This would add a similar mechanic to Yasuo's whirl wind making him not completely reliant on his boulder being up (by using terrain that exists already, or another champion's summoned terrain) but giving him another choice for a mechanic if it is needed. This would offer extra dueling potential and less needing to worry about where on the map you're fighting as Gnar. The boulder should still be able to be picked up if gnar walks over it, instantly removing the terrain for Allies and Enemies. Like a E that can be removed when desired.