The Great Abomination

The Great Abomination is a hardmode boss that has a 0.3% of appearing every day once the ML is defeated. The boss looks incredibly difficult, but most attacks deal little damage.

Introduction
If it will appear on that day the sun and moon will be dimmer and the clouds will simply puff out after a while. Stars might fall from the sky (literally drop from the background). Once it reaches noon of that day, the celestial bodies will be even dimmer than before. At 4:00 PM, a huge silhouette of TGA will gradually rise from the mountains, taking about 2 hours to fully rise. Then, at 6:30 PM, it will reveal itself, and the battle will begin.

Phase 1
The boss is invincible in this stage.

Form 1
The boss will immediately attack with any of its Phase I attacks, and the player(s) have to dodge these.