Mountain

 is a Tier 5 Tank that upgrades from Conqueror and Mega Grower at level 60.

Design
The has a barrel like the Builder's, but where the Builder tapering tip would be there's a very short hexagon shape made out of 2 trapezoids placed end-to-end. Attached to that structure is the actual Builder tip from where it fires blocks.

Technical
The is extremely unique as its blocks are able to grow upon impacting each other. This consumes the newest-fired block and grows the older one.