It isn't even just Frosmoth. I chose Frosmoth as a sort of meme alt to Volc, but people are heavily unfavorable toward the duck and calling Gastro bad. Thus, the team must be garbage, lol. Frosmoth also doesn't always get passed to, it's either Moth, Dirge, or Breloom that usually gets passed to.
The point is that I literally slapped together a meme team that gets wins
because of Shed Tail. Unhealthy doesn't inherently mean broken. Unhealthy means problematic without it being omnipresent. It puts you into an advantageous state without costing you much of anything.
Shed Tail vs U-Turn/Volt Switch:
Shed Tail: Costs half of your HP to pass a 25% HP Substitute to ANY Pokemon on your team at any time (assuming you have the HP to use it first.) Free SubPassing without needing to directly interact with the opposing Pokemon, which means unless they commit to smacking you for damage, you get into a far better board state than them. Only stoppable by taking too much damage, or by being Taunted. (Not much carries Taunt right now.)
U-Turn: Direct contact with the opposing Pokemon to switch. Stoppable by Protect. Activates abilities and items like Rocky Helmet, Rough Skin, Static, Flame Body, Red Card, etc.
Volt Switch: Non-direct damage to the opposing Pokemon to switch. Stoppable by Protect, Lightning Rod, Volt Absorb, and Ground types. Doesn't activate most things that U-Turn does, except for Red Card.
Shed Tail is very much a major upgrade to VoltTurn right now. The fact that it doesn't need to interact with the opponent to pass off, and doesn't activate anything on the opponent's side while giving you a Substitute to a good setup Pokemon or check/response Pokemon to take a free hit or two (not counting Infiltrator, Multi-hit moves, or Sound based moves) is a HUGE advantage. Especially if you haven't committed your Tera yet. The only true ways to stop it are denting Orth so hard its Sitrus Berry can't restore it to 50%+ (or OHKOing it), or Taunting it. However, as stated above, not many Pokemon are carrying Taunt right now. It's like... I can only think of 2 Pokemon off the top of my head that I remember/have seen carrying Taunt recently; Grimmsnarl and some variants of Corviknight. There's a third I've ran into but I can't remember what it is.
"Buh Orthworm is so bad! It can only get one per game!"
Not if you have a brain to play it well. With Pokemon like Garchomp, Ting-Lu, and Great Tusk running around, it isn't hard to swap it in for a free Earth Eater activation and either Shed Tail immediately (if it isn't a Tusk/Mix Chomp), or double out into something else on a predicted play. I've had a couple of games where I've gotten THREE Shed Tails off of a single Orthworm before because of this.
Shed Tail is cheesy as all hell, even if it may be a fun time to just swap around for a bit until you get to the point of "IT'S TIME!" and you pass into your meme Pokemon. It absolutely feels like one of "PIMPNITE"'s Magikarp sweep videos with a Baton Pass chain. But hey, what do I know? I use bad Pokemon regularly on teams, and sit around 1300-1500 on ladder from not playing much.