Osmium

 is a Tier 5 Tank that upgrades from Mega Smasher and Iron at level 60.

Design
The is simply a combination of Iron and Mega Smasher. It looks very similar to Mega Smasher, retaining its signature bulkier shell, but with its color changed to match Iron's unique shell.

Technical
The retains Mega Smasher's increased stats, with the added perk of debuff immunity.