Be careful when defending against Stun Gas Bloon, as all monkeys that attack it will be stunned for 1 turn, guaranteeing that it cannot attack or reload at all on the next turn. Powers and Heroes are preferred for handling them.
Heroes cannot be stunned by damaging it. Quincy is by far the more reliable choice for popping Stun Gas Bloons, alongside Adora with her passive activated.
The Stun Gas Bloon can take advantage Monkeys with multiple ammo, especially those who are defenders or attack multiple targets.
Mortars have no control over hitting a target, so Stun Gas Bloon is a good counter to them, especially The Big One.
Blade Maelstrom's passive is not affected by the stun effect. However, it does prevent ammo from being used, particularly if attempting to use its Defender bonus.