Replacing Scott Lang
Hank Pym and Hope van Dyne needed help from Scott Lang to retrieve Janet van Dyne from the Quantum Realm, following Lang and Janet becoming entangled. However, Lang was on house arrest due to his involvement during a conflict amongst the Avengers, so they took Lang's ankle monitor off and put it on the Replacement Ant. Pym had the ant replicate Lang's daily routine, which Pym and Hope van Dyne had figured out by observing him. It did performed Lang's routine uninterrupted, at one point watching television. Luis, who had spent the night at Lang's house, found the ant watching the news and eating Froot Loops, getting startled. At first, he believed the ant to be Lang. Doing this later caused the ant to knock of a plant, despite Luis' attempts to prevent it from doing so. At one point, the ant took a bath. Cassie Lang saw the ant, amused, and rushed downstairs to cover for her father, since the FBI had arrived and were suspicious that Scott Lang was not present. The ant continued to "bathe" while Lang pretended to be sick, causing agent Jimmy Woo to leave once he was sure the ankle monitor had not been tampered with.
Surviving the Snap
The ant continued to replicate Scott Lang's routine while Lang, along with Hank Pym, Hope van Dyne, and Janet van Dyne prepared to experiment with the Quantum Tunnel, hoping to get energy from the Quantum Realm to help Ava Starr. However, as Lang entered the Quantum Realm, the Titan Thanos killed half of all life in the universe, including Hank, Hope, and Janet, leaving Lang trapped in the Quantum Realm. Thus, with nobody to tell it to stop, the Replacement Ant continued playing with Lang's drum set, having survived the Snap.
- Ankle Monitor: As part of its mission to impersonate Scott Lang, the Replacement Ant was given Lang's ankle monitor. The monitor tracked the ant as it replicated Lang's daily routine, so that the FBI was not made aware that Lang had escaped his house arrest.
- Scott Lang's House: The replacement ant lived at Scott Lang's house in order to replicate Lang's daily routine, maneuvering the house the way Lang typically did.