There's nothing short of heals and buffs they can cast on you unless you're dueling. So either you accidentally aggroed a mob or just ran into one of those magic tiny stones/branches on the ground that you gotta go around or something.
I was going to suggest that it might be a momento. There are a few you can do to affect other players - mudballs, flower blossoms, murder crow strikes.....
I hate getting hit with mudballs. Watching my character standing there to shake the mud off is annoying, especially at a dye/outfit station or when trying on costumes!!!
PS4 NA Server CP 630+
(EP) | Avariella – Dunmer Templar – Magicka Healer, Main Character and Tamriel Quester (AD) | Lorabella – Imperial Nightblade – Stamina Damage Dealer, Master Thief and Werewolf (DC) | Wild-Heart – Argonian Warden – Stamina Healer, Y'ffre's Guardian (EP) | Ra’Kharjo – Khajiit Sorceror – Magicka Healer and PVP Kitten (AD) | Esthaenii – Altmer Dragonknight – Magicka Healer and Fire Mage
No crowd agro, (only the other player was there) no "stubbing my toe".
The spell looked like either the Sorcerer Encase or Dragon knight Dark Talons as I did notice objects around my legs.
Still wondering.
likely cast by a nearby NPC enemy.. a lot of players will take advantage that you have the agro, and will rush for the booty while you are CC'd or have to fight it out.