Colossal Strength
At 1st level you gain the following abilities:
Massive Build: You can use your action or bonus action to transform for a minute a number of times up to your proficiency bonus. When you enter your Monstrous Form, you may increase your size by one category. You have advantage on Strength checks and saving throws, and your carrying capacity is considered that of your transformed size at base.
Crushing Strikes: Your unarmed strikes deal 1d8 + your Strength modifier bludgeoning damage.
Sheer Size
At 6th level you gain the following features
Trample: You can move through the spaces of smaller hostile creatures. The first time you enter a creatures space, it makes a Dexterity saving throw (DC 8 + your proficiency bonus + your Strength modifier) or takes 1d8+your strength modifier bludgeoning damage and be unable to take an attack of opportunity against you.
Smasher: Your melee attacks deal an additional die of damage to objects and structures
Titanic Resilience
At 11th level you have unmatched resilience.
Stomp: As a bonus action, you can stomp the ground, creating a shockwave that affects creatures within 15 feet of you. They must succeed on a Strength saving throw (DC 8 + your proficiency bonus + your Strength modifier) or take 1d8 + your strength modifier bludgeoning damage and be knocked prone. If the ground in that area is earth or stone, it becomes difficult terrain for other creatures until cleared.
Tectonic Slam: As an action, you can slam the ground with immense force. Each creature within a 20-foot cone in front of you must make a Strength saving throw (DC 8 + your proficiency bonus + your Strength modifier) or be pushed back 20 feet and knocked prone. Once you use this feature, you can't use it again until you finish a long rest.
Tread Underfoot: Attacks you make against prone creatures deal an additional die of damage.
Colossus Fury
At 18th Level you become a living colossus, wielding incredible power.
Titan's Rage: As an action, you can enter a rage that lasts for 1 minute. While raging, you have advantage on Strength checks and saving throws, and your unarmed strikes deal an additional 1d8 damage. Once you use this feature, you can't use it again until you finish a long rest.
Earthshaker: When you make a successful melee attack, you can choose to deal an additional 2d6 bludgeoning damage and force the target to make a Strength saving throw (DC 8 + your proficiency bonus + your Strength modifier) or be pushed 20 feet and knocked prone.