Hokey

Hokey was a house-elf that belonged to Hepzibah Smith.

Hokey was accused and convicted of accidently poisoning her mistress's cocoa. Hokey remembered putting something into the cocoa that turned out not to be sugar, but a leathal poison. The Monitry put it off to an accident given the fact that Hokey was old and probably confused. However, it is likely that Tom Riddle poisoned Mrs. Smith (in order to steal Hufflepuff's Cup and Slytherin's Locket and then magically changed Hokey's memory to make her look like the guilty party.

In a memory seen through the Pensieve, Harry Potter describes Hokey as "the tinest and oldest house-elf [he] had ever seen". Her head did not reach the seat of Mrs. Smith's chair and she had papery-skin and wore a linen sheet as a toga.