Just off relevant answer: I had a Mountain Dwarf Barbarian that had to break through a hatch. After a couple embarrassing strength rolls (with advantage no less), he climbed the 200 foot surface adjacent to it, pulled out his maul, and did a Thor dive straight into the hatch. The hatch took as much damage as the dwarf, and we were through.
On topic answer: A rogue snuck into a mountain cave to scout and proceeded to a.) Blow their stealth, b.) blow their perception, and c.) blow their initiative. The giant inside landed three high damage crits. Then, it carried the rogue out and threw the rogue as a boulder attack, which crit and took down a wounded PC, who proceeded to fall from their hiding spot (1 auto failed death save) and then roll a 1 on their death save at the start of the next turn. When the giant waged into battle, I had it pick up those two downed corpses and dual wield them.
Throwing the rogue was a way to let the PCs get their items back, and a way to potentially allow them to heal the rogue before it had three failed death saves (although they assumed the rogue was dead and never checked). Dual wielding the corpses was a way for me to reduce the damage the giant was going to deal to a suddenly underpowered group. It was horrific, though, to see in play. The rogue player doodled it all down and that ended up being on my binder cover for a while.
