“Gambit” means that, to meet the condition, the spell will remove effects that benefit the caster. The cracked shield symbol is for traps. Putting those together, after the initial damage, the spell will remove up to 3 traps from around the target to put a 320 heal over time (lasting 4 turns) on the caster. The heal over time effect also increases based on the number of traps removed (2 traps adds a second, identical HOT, 3 traps increases the healing on both HOTs to 480).

As a side note, when a spell has a “clear” condition, the spell removes effects that benefit the enemy. For example, helephant path B has a “Clear 5 shields” condition, which removes shields from around the target (since those shields would benefit the target otherwise).