Rick, Ford, Oak, Wily, and P&F decide to kill the Marvel Cinematic Universe. They detect a dimensional rift opening in exactly a year, so they use that to invade MCU. But due to the nature of the rift, no one in the group can pass through it, so their army will be released and incapable of being accessed by the gang afterwards.

• All members are on board and working together. They each have a permanent portal to a base they created where the dimensional rift will open, so they can travel between their worlds if beneficial.

• They can use inventions they already have.

• Bio weapons like Pokemon or the shapeshifter can enter. It's Phineas, Ferb, Wily, Ford, Rick, and Oak specifically who can't. On that note, Oak doesn't have EVERY Pokemon ever. Just the ones he can hunt down in the time span, and starters.

• No one in the MCU knows about the invasion. Some might have caught on to a rift opening, but can't predict what will immediately come out.

• The rift opens right above Stark Tower. It opens at exactly midnight, and remains open for 24 hours before closing.

• Any personal life issues are ignored and no outside forces try to stop them.

• Phineas and Ferb have had experience with Marvel, and share the information with the others. They only have that much knowledge, as well as anything they can find on Wikipedia.

• The gang wins when every living being in the MCU is dead. If their army is destroyed or put into a position where they can't fight, they lose. If the rift closes but the robots are still fighting, battle continues.

• The gang are watching the whole fight.

Given the year to build their army, can they kill every last soul in MCU?

Round 1) Exactly what I mentioned above.

Round 2) Ford can now utilise Bill and his weirdness, Oak captures and tames Arceus, Rick enlists the help of the Council Of Ricks. MCU is now comic Marvel universe.