Irregular verbs don’t follow the usual pattern in the present tense. Some irregular present tense verbs only change in the ‘I’ form. Some of the most common verbs in Spanish are irregular verbs.

So, in IKIMASU (to go), you change KI to KU, and get IKU. There are two irregular verbs that don’t fit the above patterns. They are KIMASU (to come), and SHIMASU (to do). KIMASU becomes KURU ...