You release a swarm of medbots towards the target in order to heal them over time.
Target is healed for 1d4 health initially and 1d4 while concentrating in the following rounds.
For each 20 success rate, you can use a larger dice:
100 - 1d6
120 - 1d8
140 - 1d10
160 - 1d12
180 - 1d20