Sir William, Happiness Hugs, is a Unique Cuddle Bear found in Whimsyshire (only Whimsyshire, NOT in Whimsydale) in Act I of Diablo III.
In combat, he has Desecrator, Molten and Thunderstorm affixes.
He has a very low chance of spawning, but if he appears, he is guaranteed to drop a book that will give player a Whimsyshire-themed portrait.
It's like a party on your head!
- This monster, along with Princess Lilian, is one of the two Unique monsters that can appear in only one of the two incarnations of the secret rainbow level, and not in both.