Botamo Shield is an ability in which the user is able to avoid being damaged. Botamo's slippery body simply has the ability to not take damage even from much stronger foes' physical and energy attacks (though it was implied there is a limit to his ability, as it was thought that Super Saiyan Blue would be able to damage), however the force from attacks could still knock him around. In the anime, he initially instead transports the damage or attacks delivered by an opponent to another dimension, negating the attack from even hitting him, and thus not causing him to even be budged by any attack. This allows the user to receive no physical harm and be able to fight for a longer period of time without ever wearing out or sustaining heavy damage. Later on, during the Universe Survival Saga Botamo's ability became the same in both the manga and anime.
In the Tournament of Destroyers, Botamo utilized this ability in his entire battle against Goku, much to his surprise. Thus, despite Goku's clear advantage in power, he was incapable of dealing any damage to the hairless bear, with Piccolo and Vegeta noting that Goku would probably need to go all the way up to his Super Saiyan Blue form if he wanted to hurt him. However, Goku manages to find a way around Botamo's ability by throwing him out of the ring, resulting in Goku's victory.
In the Tournament of Power, Botamo used this ability to defend Hit from Super Saiyan Vegeta, and then used it as a key part of the Bota Magetta technique, using his invulnerability to keep himself positioned in such a way that Auta Magetta would not be able to hear any insults.