Firstly, Happy Janmashtami! 

1. When Yashodha saw the whole universe in the mouth of Infant Krishna:- 

Lord Śrī Kṛṣṇa replied: My dear mother, I have never eaten dirt. All My friends complaining against Me are liars. If you think they are being truthful, you can directly look into My mouth and examine

 it. [ SB - 10.8.35 ]

That's when Yashodha told him to open his mouth, Sri Krishna was left with no alternative now. So, he opened his mouth, when Yashodha looked into it, she saw the entire universe in his mouth: the solar system, stars, planets, the seven oceans, and Narayana (lord Vishnu) resting on Sheshnaag with Mata Lakshmi. 

After seeing the whole universe, the supreme, and the seven oceans in the mouth of Sri Krishna, she realised the truth but shortly after that because of another leela of Sri Krishna, Yashodha instantly forgot everything she saw inside the mouth of Sri Krishna! After missing everything she took Sri Krishna within her hands affectionately. 

2. When Sri Krishna lifted Goverdhan hill for 7 days:- 

Puja of Govardhan hill began. When Indra deva saw that villagers are not nurturing him. Indra deva was outraged by this and hence, he determined to teach them a lesson by sending awful rain clouds which led to a flood in Vrindavan. Calling the Samavartaka clouds of havoc, Indra Deva ordered them upon Vrindavan with disastrous rain and thunderstorms, and that caused enormous floods that would devastate the livelihood of the residents if not stopped soon. 

As severe rains and thunderstorms ruined the land and started drenching underwater, the scared and powerless villagers approached and spoke to Sri Krishna for help. Sri Krishna lifted the entire Govardhan Hill at once with His left hand on his little finger, all the villagers along with their cows and other stuff took shelter under Govardhan Hill. For seven days they lived under the hill, safe from the truly unpleasant rains and thunderstorms. Without any hunger or thirst, they were really shocked to see the huge Govardhan Hill resting on Krishna’s little finger perfectly. But the villagers gave Sri Krishna 8 times food a day for the whole seven days.

Indra Deva finally called back the clouds of destruction, thus ending the thunderstorms and the rains. Everything was fair now, Sri Krishna asked the villagers to return home without any fear, and gently placed back the Goverdhan hill. Everyone including Nanda Maharaj, Yashodha, and Balarama were delighted. That was how the pride of Indra Deva was dealt with by Sri Krishna. He came to Lord Krishna with folded hands and begged him for forgiveness. Sri Krishna forgave him and gave him some precious awareness on Karma (duties) 

3. When Sri Krishna liberated of Kubera:- 

One day Yashoda was churning butter and Sri Krishna came near her and she took her in her arms affectionately. But suddenly she recalled that the milk is now overboiled and is dripping through  the vessel. She kept Sri Krishna aside and told her she will come in some time. When she returned to the room from the kitchen she saw butter all over the room and Sri Krishna sitting and eating it with butter all over his face as well! 

Yashodha delighted but pretended to be angry. She knew the only way to keep hold of his son. She took a rope and wooden-mortar wheel and tried to tie Sri Krishna with it but Sri Krishna didn't like being tied up, the rope was short with just 2 fingers. Yashodha took another rope and tied it from the first rope but still, it was short, she took another rope, and yet it was short! Then Sri Krishna took a rope and rolled it around his body. And now it was not short. Yashodha left him tied there. Sri Krishna saw two big trees.

Sri Krishna pulled the wooden mortar to which he was tied by his Yashodha. As he passed between the trees, the mortar stuck in between. With his mighty strength, Sri Krishna pulled it, the force was sufficient to uproot the trees and they fell to the ground. Two heavenly beings in resplendent clothes appeared from the trees and paid their appreciations to Lord Sri Krishna. Seeking his authorization they returned to their heavenly abode. Thus were Kubera's sons- Nalakuvara and Manigriva released from Narada's curse. 

Hearing the loud noise everyone rushed to the scene. Nanda Maharaja untied knots to free his child and picked him up with great relief and affection.

4. Butter and Sri Krishna:- 

~ जय श्री कृष्ण