Calvin's bath is a running gag in Calvin and Hobbes. Like many children, Calvin tends to be difficult come bathtime, but usually calms down once inside and even has fun. Most of the time, Calvin will create messes while in the tub or attempt to escape the bath. He also tries to put the water outside the tub.
Calvin takes his bath for at least 20 minutes just before bed, seemingly twice or thrice a week. In early strips, Calvin's mother would help him into the bath or even wash him. Later, though, Calvin acquired more autonomy, and would often have Hobbes as company.
The bath is located upstairs in the bathroom. It has a shower head in addition to the faucet, and a soap holder on the side. It is placed away from the sink and toilet and to the left when one enters the bathroom.
Calvin employs many methods to avoid or delay his bath time.
Calvin tends to go into hiding when his mother calls him for his bath time. He has hidden on the roof, in the chimney, in the tub with no water ("She'll never look here") and even inside the vacuum cleaner's dust bag ("She would never have found me if I hadn't sneezed").
FakingCalvin has also attempted to plant decoys in the tub or fake that he was taking his bath. None of these attempts worked, as the decoys were unconvincing and Calvin's mother could tell her son had not washed.
StrugglingWhen he can think of no better, Calvin simply throws a tantrum and refuses to take his bath. He then has to be forcefully carried upstairs by his mother, and even then may trash the bathroom or complain for some time before actually entering the tub.
Calvin has also tried to convince his mother that he did not need baths to stay clean. Instead, he suggested using the vacuum cleaner or licking himself clean in the manner of cats. He has also once cleaned himself by sitting in the toilet bowl, flushing it and considering it as bathing done.
Calvin tends to visualize disastrous scenarios resulting from taking his bath. He has interpreted his pruned extremities as harbingers of menace, foreseen the hot water turning him into popcorn and imagined being attacked by a monster made out of soap bubbles. These dangers are metaphors for Calvin's fear of baths, just as Calvin's Killer Bicycle and vicious baseball represent his fear of riding and getting hit by balls, respectively.
Despite his apparent hatred of baths, Calvin has been known to enjoy himself when playing in the tub. Although his play sessions start out as fairly typical routines with toy boats, they may snowball into elaborate fantasies for which Calvin misuses the bathroom appliances. Calvin once poured ink into the bathtub as if an oil tanker run aground.
When not playing with his toys or with Hobbes, Calvin may act out fantasies to relieve the boredom of bath time. He has pictured himself as a snapping shark, a breaching whale, and a Godzilla-like monster on a rampage. Calvin also once said that he believes there may be sharks in his bath.
Calvin also complains about the time he has to spend in the bath. He believes it will soil his record and historical significance for future generations to know he spent on average four full days a year in the bath.