[Fleecemane Lion] vs [Languish]

[DblNcklHog]

Playing EDH and my opponent drops {Fleecemane Lion} manage to burn it before he gets monstrosity next turn.

Next time, if I use [Languish] once he gets monstrosity, I can still board wipe and take care of [Fleecemane Lion] because:
1. I'm not targeting, thereby ducking hexproof; and
2. Reducing toughness to zero without causing any combat damage, thereby not "destroying" his creature.

Can you please verify if I have interpreted the rules correctly?

Sorry everyone, been a longtime cannot remember if it's curly brackets or square brackets, tried both, don't seem to get hyperlink to cards.

[Thanatos003]

Playing EDH and my opponent drops {Fleecemane Lion} manage to burn it before he gets monstrosity next turn.

Next time, if I use {Languish} once he gets monstrosity, I can still board wipe and take care of [Fleecemane Lion] because:
1. I'm not targeting, thereby ducking hexproof; and
2. Reducing toughness to zero without causing any combat damage, thereby not "destroying" his creature.

Can you please verify if I have interpreted the rules correctly?

Sorry everyone, been a longtime cannot remember if it's curly brackets or square brackets, tried both, don't seem to get hyperlink to cards.

[Themugz]

Playing EDH and my opponent drops {Fleecemane Lion} manage to burn it before he gets monstrosity next turn.

Next time, if I use [Languish] once he gets monstrosity, I can still board wipe and take care of [Fleecemane Lion] because:
1. I'm not targeting, thereby ducking hexproof; and
2. Reducing toughness to zero without causing any combat damage, thereby not "destroying" his creature.

Can you please verify if I have interpreted the rules correctly?

Sorry everyone, been a longtime cannot remember if it's curly brackets or square brackets, tried both, don't seem to get hyperlink to cards.

Yes if there are no other static buffers to the creatures P/T - it will be a 0/0 and die