Conversation so far:
What happened in 1988?
In mid-1988, Hogan wrestled at house shows in singles competition with his "War Bonnet", a red and yellow gladiator helmet with a fist-shaped crest.
did he win?
CANNOTANSWER.
who was mega powers?
Together, Hogan, Savage, and manager Miss Elizabeth formed a partnership known as The Mega Powers.
what did they do with the mega powers?
After Savage became WWF World Heavyweight Champion at WrestleMania IV, they feuded with The Mega Bucks.
what happened with the mega bucks?
defeated them at the main event of the first SummerSlam.
what happened in 1989?
At the Royal Rumble in 1989, Hogan eliminated Savage from the Royal Rumble match while eliminating Bad News Brown.
did he lose to anyone?
Hogan remained WWF World Heavyweight Champion for four years (1,474 days).
In front of 33 million viewers, however, Hogan finally lost the title to Andre.

Question: when did that happen?
Self-contained rewrite: When did Hulk Hogan lose to Andre?