Pikotaro is a Metal enemy, which means he only takes 1 damage from all attacks except for Critical Hits. On the contrary, Pikotaro has very high attack damage which can kill most Cat Units in one hit. However, his backswing is also long so stalling him won't be an issue at all.
Strategy[]
Since his attack rate is quite slow and his stage does not have Assassin Bear to force lose the player when they takes too much time, using fast-hitting cats is an effective way to deal with him. Even spamming Tank Cat or Cow Cat is enough to kill him. Metal Cat can also be helpful to stop Pikotaro from getting near to your base. You could also use a fast attacking critter, such as Catasaurus, however you would require good luck to get a critical on the 1st hit, either that or send out a fast meatshield and Catasaurus, then get a critical hit before his next attack.
Encounters[]
This enemy has always appeared at 100% strength magnification.
Turn the animation on and off using the switch in the upper left. Clicking the viewer background enables scrolling and zooming with the mouse if on desktop. Note that browser zoom may cause issues with scrolling and zooming. A list of available backgrounds can be found here. For more info on usage, see here.