Tahm Kench and other Champs' possible Backstab Mechanics

By backstab I mean to fight against your own team, I knew a few champs had abilities that can be used to backstab before Tahm Kench, but his ability to pick you up and spit you somewhere added a very easy way for someone to troll and backstab. A few other heroes that can do similar things are: Anivia Ice wall blocking you near enemies or denying you a kill, Alistar can W enemy champs into killing range of you, Blitz can pull them to you, Thresh can somewhat knock or pull them into you.

Anyways, I've only played about 30-40 games with a Tahm Kench on my team, but at least 5 of them the Tahm Kench seemed to be deliberately killing me. I was usually a squishy character such as Nami, Lux, Lulu, or Cait, and Tahm would frequently pick me up and launch me straight into the middle of 3+ enemies, sometimes also under turret. A few times I said 'brb' or 'afk' for a few seconds behind turret or I was almost able to afford that item at fountain and the Tahm Kench would pick me up and toss me out into battle.

Only 2 of them were bad enough that I was certain it was intentional and I reported, but plenty of them had me questioning if they were doing it on purpose. One of these games I got support before him because Tahm Kench autolocked and didn't call any lane and then he was raging half the game and every time he was near me he would eat me and spit me out behind to make me useless the whole fight.

There's also a problem of when I'm about to finish a kill and Tahm Kench will pick me up and I won't be able to cast or do anything and the kill will get away and then he launches me way after they're gone.

Also what are some other champions' abilities you can think of that can potentially be used to backstab?