Agatha's Soul Cauldron
Lurking Roper
Overgrown Arch

   Prerequisites

What do I need to start this combo?
Overgrown Arch in exile (Overgrown Arch exiled by Agatha's Soul Cauldron in exile).
Agatha's Soul Cauldron and Lurking Roper on the battlefield.
Lurking Roper has at least one +1/+1 counter on it and does not have summoning sickness.

   Steps

How does this combo work?
1
Activate Lurking Roper using Overgrown Arch's first ability by tapping it, causing you to gain 1 life.
2
Lurking Roper triggers, untapping itself.
3
Repeat.

   Results

What do I get from this combo?
Infinite lifegain
Infinite lifegain triggers