Fun style I've been trying lately, mostly ZvT but you might get a good muta switch opportunity in ZvP if their composition allows for it.
Recommended level: platinum league or below
Our goal: to make a player stay in the game long enough to eliminate all their buildings in a base trade
What to do: this is only recommended against bio, so presumably you've scouted a second rax before a second factory and you're making your lair and baneling nest or whatever. Cool. Make a spire at your main or natural, start +1 air attack. When it finishes, start +1 air armor and start a second spire at the opposite base (if it gets scouted, it looks like you're an idiot and made two spires, if they're next to each other it looks like you're planning a huge air transition). Once that finishes you can start +2/+2 and +3/+3 accordingly.
Get however large of a ling/bane mass you need to hold off whatever push they make, but not much more. You can show mutas if you want, but keep it to ~10 or so to avoid tipping your hand. Maintain whatever ling/bane army you need in order to hold, but otherwise bank gas (do keep up with melee upgrades and stuff like you normally would). If you do make some early mutas, don't be aggressive with them, you don't want your opponent to start making turret rings or widow mines or thors or whatever.
Once you have enough gas to max out on mutas or just to make a ****load of them, hold down that T key. Fly into their main, wreck stuff, pop between bases, micro the **** out of them and kill as many buildings as you can. Targeting down bases is A+ too.
All players will try to stop you, and some players will leave when they realize they can't. But every so often a magical player will say "**** it, I'M GOIN' ALL IN" and march his army across the map. These are the live ones! Make some far off bases so you won't lose a base trade, and maybe start some new tech buildings at a far off one in case your main goes down, but in all likelihood you won't need it - this only happened because they're dead and they just haven't realized it yet. Move your army somewhere safe so you can use it you have to, but otherwise just let them continue on their merry way thinking there's still a shred of hope they can win the game.
With your mutas, target down all their buildings. Ta da! They lose. Say something snarky in chat (or maybe just an offensive gg - make sure you hit "return to game" when the score screen pops up) when they can't reply because losing doesn't give you the "return to game" option.
In replay form:
https://drop.sc/replay/7158855