Nice sentence! It is almost correct. The only thing to change is the ALL CAPS word — that looks like shouting. Use normal lowercase letters.
Correct sentence:
The curious mouse stops by and squeaks.
- Who? "The curious mouse" — this is the subject (who the sentence is about).
- What does it do? "stops" and "squeaks" — these are the verbs (the actions). They are in the present tense and match the subject.
- "and" — this word joins the two actions together.
- End punctuation — there is a period at the end, which is correct.
If you want to say it already happened, you can use the past tense: The curious mouse stopped by and squeaked.
Try reading the corrected sentence out loud. Can you write one about a cat now?