Until it drops.
Terraria Community Forums
TTSp00k the Invincible
Golden 5hotgun
Lel
Golden 5hotgun
That was funny
Azu
It wasn't a joke. Have fun for four more hours.
Aditya
Slimy Saddle is 25% drop chance and Honeyed Goggles is 5% drop chance. It shouldn't take long to get the slime mount.
Azu
That's in 1.3.
Aditya
It doesn't say anything about an increase in drop chance for 1.3 on the wiki. Only in expert mode, which is higher than 25% and 5%.